We are pausing our live coverage of Travis King, the US soldier who crossed the border from South Korea to the North without authorisation.

It's still unclear why he fled to North Korea. Pentagon officials are investigating the incident, and have said his safety is Washington's top concern.

There has been radio silence from Pyongyang and behind the scenes, officials are desperately trying to open communication lines.

We've learned from local media in the last few hours that King served two months in a South Korean jail on assault charges and was released on 10 July.

His mum has also told US television that she couldn't believe what her son what had done, and wished he was home in the US safe.

Our writers on this page were Kelly Ng in Singapore and Ali Abbas Ahmadi in London, with editing by Ayeshea Perera and Joel Guinto.

North and South Korea are technically still at war after the 1953 Armistice and US soldier Travis King's daring border crossing underscores the division between the two nations.

After news King's dash to the other side of the DMZ broke, Pyongyang fired two ballistic missiles into nearby waters, an apparent response to the arrival of a US nuclear submarine in the South.

Just last week, the North fired an intercontinental ballistic missile after threatening retaliation against what it said were recent US spy plane incursions over its territory.

Pyongyang is expected to show off more of its military arsenal during the Armistice anniversary on 27 July, which it considers as a day of victory. In the run-up to the event, it has engaged in strong rhetoric over its nuclear capabilities.

It is within this context that authorities in Washington are trying to figure out the case of Travis King.

Image source, EPA

Jean Mackenzie
Seoul correspondent

Behind the scenes, diplomats and military officials are desperately trying to talk to the North Koreans to find out what is going on, but engaging them is not easy, especially when you are the United States.

The Pentagon has tried to make contact, but as the two countries do not have diplomatic relations, the Swedish embassy in Pyongyang tends to negotiate on behalf of the US. Currently its diplomatic staff are not in the country, because of the ongoing border closure.

Both the UN Command, that runs the border area, and the South Korean military have direct phone lines to the North Korean military, that they call daily to check in, though the North Koreans do not always pick up. The UN Command says it has contacted North Korea through this channel, but it is not clear whether they have responded.

Who, if anyone, they are talking to right now is a mystery - and they are yet to send a message to the world.

Image source, Getty Images

Travis King was on a tour of the Joint Security Area (JSA) between North and South Korea when he crossed the border, the UN Command said.

A professor in South Korea has said that Panmunjom is the likely site of the crossing, according to AFP.

Learn more about Panmunjom in this video.

It's been almost a day since news broke that US soldier Travis King voluntarily crossed into North Korea and Pyongyang has not issued a statement about the incident.

On Wednesday, the state-owned Korean Central News Agency made no mention of the rare border crossing. Instead, its headlines centered on the death anniversary of its founder Kim Il Sung and the development in various local industries.

The North Korean mission at the United Nations has also not responded to requests for comment, according to Reuters news agency.

Some analysts say Pyongyang may still be deliberating over how to handle such an unusual development.

Travis King is not the first US soldier to voluntarily cross the DMZ into North Korea.

In 1965, four US soldiers defected to North Korea where they were held as prisoners and made to star in propaganda films as Western villains.

Only one of them was freed after 40 years, Charles Robert Jenkins. The three others reportedly died in in the reclusive state, including James Dresnok, who suffered from a stroke.

Following his release in 2014, Jenkins surrendered to the US Army. He was given a 30-day prison sentence and a dishonourable discharge. He eventually settled in Japan with his family.

Jenkins died in 2017 at the age of 77.

It is unclear if King had defected to the North.

Image source, Getty Images

Defections across the Demilitarized Zone are rare and extremely dangerous. Here's a look at other dramatic crossings between the Koreas:

• In 2017, a North Korean soldier fled across the border in a hail of bullets. Oh Chong Song, then 24, crashed a military vehicle and dashed into the South while under fire from his comrades. He suffered several gunshot wounds but was pulled to safety by South Korean soldiers.
• In 1984, Russian student Vasily Yakovlevich Matuzok's sprint for freedom from the North to the South sparked a 30-minute gun battle that killed three North Korean soldiers and one from the South. The 22-year-old made the dash while touring Panmunjom. He said it was his ''very first opportunity to go to the West''.
• North Korean journalist Lee Soo Keun's defection through the Joint Security Area in 1967 also sparked a gunfight. The South hailed Lee as a hero but executed him two years later, after convicting him as a spy for the North. A Seoul court absolved Lee of espionage in 2018.
• American soldier James Joseph Dresnok ran into a North Korean border village in 1962. During his time there, Dresnok was cast in several North Korean films, mostly starring as an American villain.

Image source, Getty Images

Some details have emerged on what Travis King may have been facing disciplinary action for.

South Korea's Yonhap news agency quoted "legal sources" as saying that the 23-year-old private second class was fined for "repeatedly kicking" the back door of a police patrol vehicle in Seoul's Mapo district.

King was uncooperative and shouted "foul language" at police trying to apprehend him.

He was also suspected of punching a Korean national at a nightclub in September, the report said.

Citing "legal sources", Yonhap said King was fined 5 million won (US$3,950) by a Seoul court on 8 February on various charges, including inflicting damage on public property.

It is not clear if this is why King spent two months in jail, as reported earlier.

Image source, Getty Images

The Demilitarised Zone (DMZ) between North and South Korea is known as one of the most dangerous places in the world.

The 150 mile (240km) long border is filled with landmines, surrounded by electric and barbed wire fencing and surveillance cameras and armed guards are supposed to be on alert 24 hours a day.

Tens of thousands of troops guard it on both sides.

In total, it is about 1.5 times the size of Seoul and almost twice the size of New York City.

The strip of land, which is 2.5 miles wide, attracts thousands of tourists each year who come to see one of the most highly militarised areas in the world.

Dozens of people try to flee North Korea every year, but defections across the dangerous DMZ are rare.

Kelly Ng
Reporting from Singapore

Travis King's presence on North Korean soil could give Pyongyang a bargaining chip when dealing with the US during a particularly tense time, experts say,

"Pyongyang might use him as a propaganda tool to criticise the US military... King may well show up in North Korean state media at some point in the near future," says James Fretwell, an analyst at Seoul-based specialist site NK News.

In the past, the North had held US citizens for a few months to a few years.

"But a lot depends on how long his interrogation, and maybe his Covid-19 quarantine, lasts," Fretwell told the BBC. North Korea still maintains a strict border lockdown in response to the pandemic.

"The North Koreans might also be scratching their heads over how to react to the situation, since they were probably just as surprised as anyone to see an American walking across the border," he added.

However, South Korean politician Tae Yong-ho tells Reuters that detaining an American soldier for the long run is "probably a not very cost-effective headache" for the North.

Image source, Getty Images

If you are just joining us, we have some updates from the mother of Travis King and from South Korean officials regarding the US soldier's border-crossing to the North. The central question of why he did that, however, remains unclear.

Here's what we know so far:

• Officials in Seoul have confirmed that King, 23, was released from a South Korean prison on 10 July after serving two months for assault charges
• He was escorted to the airport for a US-bound flight but did not board the plane. Instead, he joined a tour of the DMZ
• US authorities have said that King crossed the border "wilfully, of his own volition". King is believed to be in North Korean custody
• King's mother Claudine Gates tells ABC News she could not imagine her son doing such a thing. He "had to be out of his mind", she says.
• The Pentagon says it is concerned for King's welfare and is "closely monitoring and investigating the situation". US Forces Korea is also investigating the incident
• Hours after news of King's detention broke, Pyongyang fired two ballistic missiles into the nearby sea - analysts say they are likely a response to the arrival of a US nuclear sub in the South, and not to King

Yuna Ku
BBC Korean Service

Kyung-ryoon Lee, whose company offers tours of the Demilitarized Zone, expects the Travis King incident will make it harder for companies like his to get approvals for future tours of the Joint Security Area.

The JSA, also called the Panmunjom, straddles the border between North and South Korea. It is the only portion of the DMZ where the military forces of the North and South stand face-to-face.

“[The United Nations Command] often changes their decision on whether to permit tourists in or not, and I think this incident is going to make it harder for us to do JSA tours for a while," Lee told the BBC.

Lee, who founded DMZ Spytour, says his company took 2,000 tourists to the DMZ and JSA before the pandemic.

"We give tourists a lot of precautions, saying, 'Don't do this, don't do that, you could be arrested by the North Koreans'," he said.

Lee added: "There's nothing they can do [to help] once [someone crosses] the [military demarcation] line, because you the soldiers can’t step into the line and bring you back."

You've likely noticed that acronyms have been peppered throughout our coverage as we describe the situation surrounding the detainment of a US soldier in North Korea.

We figured it would be helpful to spell out these acronyms, as you're bound to see them again in our reporting.

Here is a quick breakdown:

• DMZ: the Demilitarised Zone between North and South Korea. It is known as one of the most dangerous places in the world - filled with landmines and barbed wire - and is monitored by guards from both sides 24 hours a day
• JSA: the Joint Security Area located within the DMZ. It is the only site where soldiers from both sides stand face-to-face, in the presence of the United Nations Command
• UNC: the United Nations Command, which keeps a permanent presence in the JSA to maintain armistice and facilitate negotiations between North and South Korea
• USFK: the United States Forces Korea is the command representing more than 20,000 US soldiers based in South Korea, headquartered in Pyeongtaek
• KPA: the Korean People's Army is the military of North Korea, led by its commander and the country's leader Kim Jong Un
• DPRK: the Democratic People's Republic of Korea, the official name of the country of North Korea

Image source, US Forces Korea

North Korea fired two short-range ballistic missiles on Wednesday morning, Seoul's military said - an apparent response the the arrival of a US nuclear ballistic missile submarine in the South.

The launches were detected between 03:30 and 03:46 local time - hours after reports emerged that the US soldier Travis King had been held in North Korea after crossing the border from South Korea.

The US sub, identified by South Korean officials as the USS Kentucky, docked in Busan port on Tuesday.

Leif-Eric Easley, a professor at Ewha University in Seoul, said Pyongyang's latest missile launches are "probably unrelated" to Travis King's border-crossing, but "such an incident doesn’t help matters either".

"The Kim regime is likely to treat a border crosser as a military, intelligence, and public health threat even though it is more likely that such an individual is mentally distressed and acting impulsively due to personal issues," Prof Easley said.

Image source, Reuters

US soldier Travis King is not the first American to be detained by North Korea in recent years.

Some may recall the story of Otto Warmbier, a US student who was jailed in Pyongyang in 2016 for stealing a hotel sign.

Warmbier was released after 17 months on medical grounds, but arrived home seriously ill and died a few days later.

His parents have accused North Korea of torturing their son. In interviews at the time, they said their son was unresponsive, had his head shaved, was blind and deaf and that his limbs were "totally deformed".

North Korea has denied ever torturing the student, saying instead that Warmbier contracted botulism while in prison, though US doctors have found no trace of this.

The parents' account has also been disputed by local US media, who said they had obtained a coroner's report showing no evidence of torture.

The report showed Warmbier died from brain damage caused by a lack of oxygen, the Cincinnati Enquirer reported.

It is still unclear what exactly happened to Warmbier, but his story has raised fears about the treatment of detainees in North Korea.

You can read more about Warmbier's story here.

Travis King was released on 10 July after serving around two months in a South Korean prison on assault charges, a Seoul official has told AFP.

The 23-year-old had been investigated for assault in September 2022, but was not detained at the time, AFP reported citing South Korean police. Details of the assault charges are unclear.

Reports say King, a private second class who had been in the army since 2021, was then put under military observation for about a week in South Korea.

King had been escorted to the airport in Incheon, near Seoul, for a flight back to the US to be separated from the army, US officials told CBS News, BBC's partner in the US.

But he did not board the plane after parting ways with his escort.

He is reported to have left the terminal to embark on a tour of the Demilitarised Zone between North and South Korea.

Image source, Getty Images

Jean Mackenzie
Seoul correspondent

If, as is being reported, the solider was able to leave the airport in Seoul on Monday, without boarding his flight home, and join a tour of the North Korean border on Tuesday, it appears his move was pre-planned.

The host of the North Korea News podcast, Jacco Zwetsloot, worked for a tour company in 2012 that took US soldiers to the JSA. He told me that there was “no way this person could escape from the airport one day and book onto one of these tours the next”.

He explains it usually takes 3 days to be authorised to go on one of these trips. You need to submit your passport number and military ID to the UN Command, which operates the area.

“When I was leading the tours, we had to change the turnaround time from 48 to 72 hours because there were too many mistakes,” he said.

Also, since the pandemic, it has been much more difficult to get on these tours. They only restarted recently, and it seems there are just two companies offering tours to foreigners. To book this would have required research and planning.

Anthony Zurcher
BBC North America correspondent

The US soldier Travis King's crossing the border into the Koreas' demilitarised zone could turn into a full-blown crisis for Joe Biden's administration.

The incident comes on the day that a US nuclear missile submarine arrived in the South Korean port of Busan - a visible demonstration of US military strength that had angered the North Koreans.

While King's intention to enter North Korea is unclear, his presence gives the North and its leader Kim Jong Un a new bargaining chip to use when dealing with the US.

If the soldier is an unwilling detainee, Mr Biden could face growing pressure to arrange his release. And the North Koreans will certainly use his presence on their soil as a propaganda tool.

Read more here.

Travis King's mother told ABC News, external she could not imagine her son crossing into North Korea without authorisation.

Claudine Gates told the American television network she thought her son "had to be out of his mind" although she was not aware that he had any history of mental illness.

"I am so proud of him. I just want him to come home, back to America," she said.

Gates, who lives in Racine, a city in midwestern US state Wisconsin, said she last heard from King a few days ago when he said he would soon be returning to his base in Fort Bliss, Texas.

She said the US military informed her of her son's detention on Tuesday.

Reports said King, 23, had recently been released from a South Korean prison where he was held on assault charges.

Image source, Getty Images

Pyongyang has detained at least 20 US citizens since 1996.

Here are some notable cases from the past few years.

• Otto Warmbier – A student at the University of Virginia, Warmbier was arrested as part of a tour group in January 2016 and sentenced to 15 years of hard labour. Shortly after his sentencing, he fell into a coma in unclear circumstances, and was released in 2017. He died shortly after.

• Bruce Byron Lowrance – The 60-year-old from Michigan was detained in October 2018 after illegally crossing into North Korea from China. In a rare move, he was released only a month after being detained. US officials suggested his quick release may have been an attempt to improve relations with the US following high-profile talks with President Donald Trump.

• Kim Hak-song, Tony Kim and Kim Dong-chul – Two academics at the Pyongyang University of Science and Technology and a businessman - all US citizens of Korean descent - were arrested on spying and other charges in 2016 and 2017. They were released together in May 2018, ahead of talks between US President Donald Trump and North Korean leader Kim Kong Un.

• Evan Hunziker – Hunziker, then 26, was detained by North Korean authorities in 1996 after swimming drunk and naked across the border from China after being dared to do so by a friend. He was held for three months on spying charges, before being released in November 1996. He killed himself a month later.