Derek Cai
BBC News, Singapore

Kim arrived at the border station of Khasan in Russia's Primorsky Krai region about an hour ago.

It is unclear how long he will stay in Khasan, or if his armoured train needs its wheels replaced to run on Russia's larger tracks.

What we know is that the journey from the station to Vladivostok will take another five to six hours, according to our analysts tracking the train.

Kim has already trundled about 15 hours north-east from Pyongyang. His train is moving slowly - about 50km/h (31 mph) is the estimated pace from earlier reports on the train.

State media are now also reporting Kim's arrival in Russia - an event first noted by the South Koreans.

Citing one of its correspondents in eastern Russia, the RIA state news agency also posted a video of a train with dark green and grey cars, which it said was carrying the North Korean leader.

We have not yet seen confirmed vision of Kim's train.

Moscow says it will give South Korea details of Kim Jong Un's visit if Seoul asks for it, says the Russian deputy foreign minister Andrei Rudenko.

"We have a South Korean embassy in Moscow. If they want, we can provide the available information," Rudenko said according to Russia news agency Interfax.

He added that Moscow will continue engaging with South Korea and the two have "common interests in terms of stabilising the situation in Northeast Asia and the Korean Peninsula."

South Korea was previously a trading partner with Russia but joined Western sanctions after the war began in Ukraine.

Here's the full quote from South Korean authorities who announced in the past hour that Kim's train had entered Russia.

The meeting between the two leaders will take place in coming days, after the conclusion of Russia's Economic Forum, the Kremlin has said.

Russian state media are reporting lines from what appears to be a Kremlin briefing just now.

A Kremlin spokesman said the talks would cover "bilateral relations, the situation in the region and in the global arena".

The leaders last met in 2019, also in Vladivostok.

Image source, Getty Images

Frances Mao

Hello to readers joining our live coverage. The BBC's Asia Online team have taken over this page from our colleagues in DC.

We've just had the first reports of Kim entering Russian territory on his armoured train - he was treated to a welcome ceremony at the Khasan border point.

But he's still about five hours journey from Vladivostok, a Russian port city very close to China, and where Putin arrived on Monday for the Eastern Economic Forum.

The US and allies believe the leaders are meeting to discuss Pyongyang supplying weapons to Russia for its war in Ukraine.

We'll take you through all the developments, the events that have led to this meeting and what we could expect later today. Stay with us.

The North Korean leader appears to have entered Russia on his private train in the early hours of Tuesday, the South Korean military has reported at a briefing.

Kim Jong Un has arrived at the Russian border station of Khasan, Japanese media outlet JNN reports citing a Russian government official.

A welcome ceremony was held for the North Korean leader at the station in the Primorsky Krai region.

It could take another five-six hours from Khasan to Vladivostok, our analysts watching the train estimate.

Russia doesn't have a lot of friends, so it needs to get closer to those who are willing to do business with it, analysts say.

Russia wants weapons and North Korea is in a position to provide "at least some support in that regard", said Samuel Greene from the Center for European Policy Analysis.

Meanwhile, North Korea wants technology for its missile programme which Russia can provide.

But there is a symbolic and political element to the visit too, says Greene. "Moscow is trying to send a signal to the West about how far it is willing to go in causing trouble around the world."

“Russia is demonstrating it is willing to help North Korea become more of a problem for the West – unless the West is willing to do a deal on Ukraine,” warns Greene.

Image source, Reuters

Kim Jong Un's reported trip to Vladivostok will be his first in four years. After taking over as leader from his father in 2011, he has made 10 foreign trips in total to five countries: China, South Korea, Russia, Singapore, and Vietnam.

• March 2018: The North Korean leader makes his first international trip to China - North Korea’s biggest economic and political ally - and meets with Chinese President Xi Jinping

• April 2018: Kim becomes the first leader of his country to cross the inter-Korea border into the Panmunjom truce village and set foot in the South. He meets with then South Korean President Moon Jae-in, and they pledge to improve ties

• May 2018: He meets Chinese President Xi again, this time taking his personal jet to China’s north eastern city of Dalian

• 10 to 12 June 2018: Kim flies to Singapore for the first ever US-North Korea summit, where he meets then US President Donald Trump. This results is a joint statement on establishing new relations between the countries, and a pledge by North Korea to end its nuclear programme, which it hasn’t

• 19 to 20 June 2018: Kim again visits China on his private jet, this time to discuss terms of its denuclearisation with President Xi

• January 2019: He travels over land via his armoured train for his fourth visit to China

• February 2019: Kim travels, again by train, to Vietnam’s capital Hanoi for a second summit with Trump. Talks collapse after the leaders disagree on lifting sanctions and how to denuclearise North Korea

• April 2019: Kim turns his attention to Russia, North Korea’s other main ally. He goes to Vladivostok for his first summit with President Putin.

• June 2019: He crosses the inter-Korea border again for a third round of talks with Trump

Image source, Reuters

Vladimir Putin's turn towards North Korea for military supplies is a sign that his invasion of Ukraine was a "strategic failure", according to a US State Department spokesman.

Speaking to reporters earlier today, spokesman Matthew Miller said that "there is no better evidence" of that failure than Putin turning to an "international pariah" for help.

US officials believe that the meeting between the two leaders is likely to include a request for North Korea to send ammunition - including artillery shells and rockets - to Russia to replenish stocks depleted over the course of the war in Ukraine.

The US will "not hesitate to impose new sanctions if appropriate" to stem the transfer of arms to Russia in violation of "multiple" UN security council resolutions, he added.

Kim Jong Un's last trip abroad was also to Vladivostok in 2019, for his first summit with President Putin after the collapse of North Korea's nuclear disarmament talks with the US. The video above is from that meeting in 2019.

Image source, Getty Images

The possibility of North Korea seeking assistance for its nuclear weapon and ballistic missile programme will likely become a "grave concern" for the international community, according to a former US deputy assistant secretary of defence.

Mick Mulroy - who is also a former CIA paramilitary officer - told the BBC that the meeting between Vladimir Putin and Kim Jong Un could take military cooperation between the two countries "to another level".

Any increased military ties between the two "would necessitate a strong reaction in the form of additional sanctions".

"It is also troubling...that Russia would likely be willing to trade expertise in nuclear weapons and their delivery systems in order to secure this agreement," Mulroy added.

"Something every country in the region will be gravely concerned about to the point of taking action to improve their own defences".

However officials in Seoul believe cooperation on things like advanced weapons technology or knowledge, to help with his nuclear weapons programme, is unlikely, as it could end up being strategically dangerous for Russia.

Read more about the Russia-Kim Jong Un alliance here.

Image source, Getty Images

As leader of North Korea, Kim Jong Un's foreign visits are usually kept a mystery. But he is known to mostly travel on his special train, believed to be inherited from his father Kim Jong Il.

It's painted in a signature green colour and rumoured to include at least 20 armoured cars, including a conference room that Kim uses for work and meetings.

Not much is known about the train, but the little we do know comes from intelligence reports and the memories of foreign officials who were allowed on board when Mr Kim's father was leader. NK news reported a Russian foreign ministry notetaker described an extravagant scene including live lobsters, cases of French wines, and meals that last for hours.

But because it's armoured the extra protection means it is much heavier than average trains, and travels at a significantly slow speed, unable to go beyond 59 km/h (37mph).

Kim's last official foreign trip using the train was also to Vladivostok, for his first summit with Russian President Putin in 2019.

Tracking the journey is very difficultpublished at 23:02 British Summer Time 11 September 2023

23:02 BST 11 September 2023

Due to North Korea’s secretive nature, tracking the train is very difficult.

The BBC Verify team is monitoring satellite images of the route for signs of the train, with the most likely point to see it as it prepares to enter Russia.

As we explained in our earlier post, Kim’s train will need to change its wheels at the North Korean border station of Tumangang - so it can run on Russia’s tracks.

Image source, Planet Labs PBC

Based on the speed of the train and the distance it needs to travel, we believe Kim’s train could arrive at the border tomorrow morning.

If this turns out to be correct, it is possible BBC Verify will obtain a satellite image of the train as its wheels are being replaced.

However, the timing will be down to luck.

If the train is delayed, the moment could be missed.

Another factor is the weather. Satellite images are taken from space and if the weather is cloudy the ground can be completely obscured.

We will be keeping our fingers crossed.

The picture we just showed you of Kim Jong Un apparently on his way to Russia were published in a North Korean newspaper.

The publication says Kim departed Pyongyang by train on the afternoon of 10 September to visit the Russian Federation.

It says "dear comrade Kim Jong-un" is accompanied on his trip by "key executives from the party, government, and armed forces agencies".

Image source, KCNA via REUTERS

We've just received some images that appear to show Kim Jong Un on his train as he departs Pyongyang, North Korea.

The pictures, issued by North Korea's Korean Central News Agency, shows the leader waving as he enters the train, said to be bound for Russia.

Image source, KCNA via REUTERS

How long will the journey take?published at 22:07 British Summer Time 11 September 2023

22:07 BST 11 September 2023

The weight of the heavily-armoured train combined with the poor state of North Korea’s railway infrastructure means it will be a long, slow journey.

The BBC has previously reported that Kim’s train is limited to about 50km/h (31mph). By comparison, London's high-speed rail runs at about 200km/h.

The journey from Pyongyang to the Russian border is about 840km (525 miles), so barring delays this would take at least 15 hours. At this speed it would take another 5 hours to reach Vladivostok.

The poor state of North Korea’s rail system has long been cited as a significant reason for the country’s poor economic performance.

North Korea has tested a variety of ballistic and cruise missiles in recent years.

It's also tested hypersonic missiles, which can fly at several times the speed of sound and at low altitude to escape radar detection, as well as others launched from submarines.

In April, North Korea tested what it called "its most powerful" missile to date - the Hwasong-18. It's a solid-fuel missile, which are generally quicker to launch than liquid-fuel ones.

It reportedly flew about 1,000km on its maiden flight. A second test launch in July 2023 saw a Hwasong-18 reach a claimed altitude of over 6,600km, with a flight time of 74 minutes.

Image source, .

The weapons Kim could offer Putinpublished at 21:31 British Summer Time 11 September 2023

21:31 BST 11 September 2023

The two leaders are likely to discuss North Korea supplying weapons in support of Russia’s war in Ukraine.

North Korea has a large stockpile of old ammunition suitable for Moscow’s Soviet-era equipment such as artillery shells. "It is likely to be one of the largest outside of Russia," says Joseph Dempsey of the International Institute for Strategic Studies in London.

Washington says North Korean munitions have already found their way to the battlefield in Ukraine, but that’s been denied by both Moscow and Pyongyang.

In return for weapons, North Korea may well ask for food from Russia. Severe shortages have been reported because of international sanctions and its closed-border policy during Covid.