Jake Kwon
Reporting from Seoul

In the last few minutes, South Korea's defence minister has tendered his resignation over the martial law.

Minister Kim Yong-hyun has apologised to the public for spreading confusion and causing distress, the ministry says in a statement.

Kim says he will take full responsibility for the martial law.

Kim will remain in his role until President Yoon accepts his resignation. There has been no word from Yoon.

Earlier in the day, the main opposition party began proceeding to impeach the minister.

After calls for his impeachment, defence minister Kim Yong-hyun has offered his resignation.

He joins other top presidential staff who tendered their resignations earlier on Wednesday - although President Yoon must accept these resignations for them to go into effect.

We'll have more on this breaking news soon.

Image source, Getty Images

As well as trying to impeach President Yoon, lawmakers are also tabling a motion to impeach South Korea's defence minister Kim Yong-hyun, according to news agency Yonhap.

It's been reported Kim was an important influence behind Yoon's decision to impose martial law.

There had already been calls for Kim to quit, including from within his own party (the People Power Party), which is now deeply divided following President Yoon's actions yesterday.

The opposition Democratic Party has also called for Kim to be investigated for treason, a crime punishable by life in prison or death, according to The Korea Times.

President Yoon was already in trouble when a video of his wife Kim Keon Hee appearing to accept a designer handbag from a Korean-American pastor began circulating last year.

The first lady was alleged to have broken rules over gifts, designed to protect against corruption. But Yoon's response threw his government into a full blown crisis.

Yoon called the video, captured by a spy camera, a stunt aimed at hurting his party ahead of key legislative elections, and said his wife had simply been too nice to "cold-heartedly reject" the 3m won ($2,200; £1,800) Dior bag.

His party suffered massive losses at those elections in April and as disquiet continued to grow, last month Yoon finally apologised on behalf of his wife - a full year after the scandal first erupted.

But Yoon ruled out allowing an investigation into the incident and public anger has only intensified since.

Image source, Voice of Seoul/YouTube

Not everyone is angry about Yoon's actions - as this Seoul resident we spoke to earlier shows.

Some politicians are also supporting the president. Hwang Kyo-ahn, a former South Korean PM who is one of Yoon's high-profile supporters, says he shouldn't be impeached.

He also backs the reasoning Yoon gave for martial law, and calls for the arrest of the National Assembly speaker who urged lawmakers to gather and block Yoon's decision.

Busan city councilman Park Jong-cheol also says he "actively supports and sympathises" with the declaration of martial law, and the mayor of Daegu, Hong Joon-pyo, says on Facebook he disagrees with impeachment.

Image source, Reuters

Tessa Wong & Leehyun Choi
Reporting from Seoul

Marina Kang, 37, says she had gone to bed early and missed the news completely.

"But this morning I woke up to so many messages from my friends and family, and all this news to catch up on. It was such a shock! I’m very relieved it wrapped up really quickly," she says in the main square of Seoul.

But one citizen expresses disappointment.

“Personally I wanted to see the martial law succeed,” says Lee Jae-whan, 45. He wants Yoon to "normalise the National Assembly and get rid of the opposition members who are cancerous to this society".

"Putting in place martial law was probably the last card that Yoon had, so I’m disappointed it didn’t happen."

Image source, Reuters

Nato's Secretary General Mark Rutte says the group is monitoring the situation in South Korea "step by step".

Rutte adds that their "relationship with South Korea is key, our relationship is ironclad... that will not change".

South Korea is not a Nato member, but is a major ally.

Laura Bicker
BBC correspondent, reporting from Seoul

What an incredible 24 hours in Korea's history.

First of all, you had a declaration of martial law that came late last night. That was a declaration President Yoon said he made because he was worried about North Korean communist forces taking power in the country. And he said he needed to take a grip.

The people here of South Korea would not accept this, neither would their politicians.

It was six hours of turmoil but it was just that, six hours.

Protesters are still here, in small numbers albeit - but they are still here either calling for him to step down or to be impeached.

President Yoon was a deeply unpopular politician. Even from the moment he took power, he only won by a 0.7% margin - that's the slimmest margin in Korean history.

So his back was against the wall, he decided to take drastic action. This martial law did not help him achieve any of his aims.

Will he step down, or will he be impeached? He's really on the political brink.

Tessa Wong & Leehyun Choi
Reporting from Seoul

Earlier today hundreds gathered for a protest at Gwanghwamun, the main square of Seoul and the focal point for rallies in the city.

The protest called for the impeachment of Yoon Suk Yeol and declared a national strike.

By lunchtime, the protesters dispersed and the square was filled with the usual crowd of tourists snapping pictures and Seoul residents going about their day.

Many Koreans at Gwanghwamun spoke of their fear and shock when they heard about the declaration of martial law last night.

“At first I was excited at the thought of not going to school today! But then overwhelmingly the sense of fear settled in, that kept me up all night,” says Kwon Hoo, 15.

Though the teen is too young to remember previous periods of martial law, he says his father told him what it had been like living with a strict curfew at night.

Image source, Tessa Wong

We've put together some of the CCTV footage showing the moment South Korea's military entered the country's National Assembly last night, after the president declared martial law:

The United States is "encouraged by the resilience of Korean democracy", its ambassador to South Korea tells the country's Yonhap news agency.

"We were concerned about the events of last night... The United States supports that democracy and the people of Korea to resolve issues peacefully, democratically and constitutionally," Philip Goldberg says.

There were concerns last night that North Korea could take advantage of chaos in the South to escalate tensions, Goldberg adds.

He says the US's commitment to South Korea is "unwavering", and the US is "always on alert and prepared".

Starting today, activists are planning days of protest rallies across the country to demand President Yoon steps down.

In Busan, South Korea's second biggest city, activists are planning to hold a rally every day for the next week, Yonhap news agency reports.

About 1,000 citizens are expected to attend a candlelight rally this evening in Gwangju, a city in the south-western corner of the country.

And protesters in the south-eastern cities of Daegu and Pohang, and the southern Jeju Island, are planning similar rallies in the afternoon.

An indefinite general strike has also begun, organised by South Korea's main labour union.

Image source, EPA

Earlier this morning we reported that President Yoon Suk Yeol's staff had offered to resign en masse following his short-lived decision to declare martial law.

We can bring you more on this now - the presidential office has announced that all senior secretaries to the president, as well as his chief of staff, national security adviser, and director of national policy, have all tendered their resignation this morning.

Yoon must accept these resignations for them to go into effect and it is not yet clear if he will do so.

Image source, Getty Images

Lawmakers have tabled a motion to impeach President Yoon. We explained the impeachment process in more detail a little earlier, but basically the process will take days, and two-thirds of lawmakers - 200 people - need to vote for it.

The opposition party almost has those numbers by themselves. The president's own party has spoken against his actions, but is still deciding how it will respond - though only a few of its members would need to vote in favour of impeachment for it to succeed.

If the motion does pass the parliament, Yoon's powers and duties would be immediately suspended, and the prime minister would become acting president.

The Constitutional Court of Korea then has the final say. If it approves the impeachment, the president is removed and an election must be held within 60 days. If they don't approve it, he can stay in office.

Nick Marsh
Reporting from Seoul

Even outside Seoul's parliament building, politicians are demanding that President Yoon step down or suffer the consequences.

"I’m very disappointed," Yang Bu-nam, a member of the opposition Democratic Party, tells the BBC outside the National Assembly, where he was taking photographs with gathered supporters.

“What the president did is shameful and we need to shout about it."

Yang was keen to assure those overseas that South Korea is not "chaos", though.

"We are a strong democracy," he said. "But Korean people want to be safe - President Yoon must resign or be impeached."

South Korea's opposition leader Lee Jae-myung calls for people "to be alert and fight together".

He adds that he thinks martial law is "something I think [the ruling party] will try again when the situation is organised and improved".

What happened last night was "a coup against the people", Lee says in a speech in front of the National Assembly, adding that the "great Korean people [had] overcome this coup".

Image source, Reuters

North Korea has not yet publicly reacted to the political chaos in South Korea, the Seoul-based news website NK News reports today.

Wednesday's edition of North Korea's ruling party newspaper Rodong Sinmun did not mention the martial law crisis, according to the NK News report.

The paper has instead published a short article highlighting demands by civic groups for Yoon to resign.

As a reminder, President Yoon said removing "North Korean forces" was part of his initial decision to impose martial law.

Image source, Reuters

Nick Marsh
Reporting from Seoul

After the chaos of last night, the mood here in front of the National Assembly feels quite relaxed.

While the politicians inside the building hold crisis talks, a couple of hundred opposition supporters have gathered on the parliament's steps demanding that President Yoon pays the price for his decision to declare martial law.

Speaker after speaker has taken to the microphone: some cracking jokes, some rallying the crowd more forcefully under a crisp blue December sky in the capital.

For now the setting is serene, but South Korea is bracing itself for what could be one of the most turbulent periods in its modern political history.

Joon Hyung Kim, an opposition MP, spoke to the BBC News channel a little earlier, explaining how the martial law order caught the country by "total surprise".

"There was a rumour, but we never believed it - [I was] really shocked," he said, explaining how he immediately rushed to the National Assembly building.

"[The police] blocked me, I wrestled a lot... but finally I got through."

Even now, Kim said he doesn't understand why Yoon made the order.

"It was very impulsive. Maybe he's not in his right mind.

"I think this is the end of his presidency... the remaining [question] is how and when it will end."

Yoon was a relative newcomer to politics when he won the presidency in 2022, in the closest race since the country began holding free presidential elections in the 1980s.

A prosecutor, he had risen to national prominence for leading the corruption case against disgraced former President Park Geun-hye who was impeached in 2016.

During the 63-year-old's presidential campaign, he advocated a more hardline approach to North Korea and on divisive gender issues.

In office, he's been known for a series of gaffes and political scandals, which have sent his approval rating plummeting and weakened his government's grip on power - culminating in last night's dramatic scenes.

You can read more about how we got here in this story.

Image source, Getty Images