Votes for the special counsel bill on the first lady are now being counted.

We're now hearing opposition MPs shouting at the ruling party lawmakers who are leaving the chamber: "Traitors, go back in".

Some members of the ruling People Power Party have just left the voting chamber after voting on the special counsel appointment in the first lady's case.

It appears they are boycotting the impeachment vote.

The bill in question calls for the appointment of a special counsel to investigate two key allegations involving the first lady Kim Keon Hee.

One is her alleged involvement in a stock manipulation scheme. The other is her interference in election nominations through a power broker.

An anonymous vote has begun into the investigation bill on South Korea's first lady.

The impeachment vote is expected to take place after this.

Emotions are running high in the parliamentary session as lawmakers shout at one another across the floor.

The speaker, Woo Won-shik, has just asked an MP to stop his YouTube streaming of the session.

The plenary session has just started in South Korea's National Assembly.

It began with the speaker reminding chamber members that the world is watching, and instructing them to maintain decorum.

Lawmakers are first voting on a special counsel investigation bill on the first lady, before moving on to the motion regarding the impeachment of President Yoon Yuk Seol.

Stay with us - we'll keep bringing updates as the voting takes place.

The motion to impeach President Yoon will soon be put to a vote, and his party has just said it will oppose it, according to Yonhap news agency.

It is unclear if the opposition coalition - which has a parliamentary majority - will get the eight votes it needs from ruling party MPs for Yoon to be impeached.

Members of the ruling People Power Party (PPP) are divided over the vote. Party chief Han Dong-Hoon on Friday called for Yoon to be suspended, saying he posted "great danger" to democracy if he remained in power - despite earlier vowing that his party would not support the opposition's impeachment motion.

On Saturday, senior members of the party said their official stance of not supporting the motion remains unchanged.

Meanwhile, people have been flooding PPP lawmakers with text messages, urging them to vote for Yoon's impeachment, according to South Korean media reports.

One MP, Shin Sung-bum, received more than 4,000 such messages on Facebook, The Chosun Daily reported.

The vote will take place anytime from 17:00 local time today. A bill involving First Lady Kim Keon Hee will first be voted on, before the impeachment motion.

Tessa Wong
reporting from Seoul

The protesters we've been speaking to here are emphatic: Yoon has to go. And if he doesn't, they say, they will continue protesting until he does. "I want the impeachment of President Yoon. He has to step down now," former police official and Democratic Party member Ryu Samyoung, 60, said over the din of protest music. "Our party will try again and again until impeachment is successful".

A 27-year-old woman, who didn't want to be named, said "if the impeachment doesn't pass, we'll continue to come out on the streets".

Image source, BBC / Tessa Wong

It's been a dramatic day already, but there's still plenty more to come.

This morning began with another surprise address from President Yoon - this time to apologise for declaring martial law on Tuesday, explaining he'd resorted to the extreme measure out of "desperation".

But despite huge pressure, the embattled leader did not offer his resignation and said he would rely on his party to help stabilise and run the country until his term is set to end in 2027.

The speech drew an immediate response from political leaders - including Han Dong-hoon, the head of Yoon's own party - who unanimously said it changed nothing, and that he must be removed from his post.

Since then, tens of thousands of protestors have packed the streets around the National Assembly, where an impeachment vote is due to happen later tonight. Yoon's supporters have been drowned out by the angry mobs calling for him to go.

We're now waiting as both sides try to shore up support in the hours before the National Assembly convenes.

To recap, 200 members must vote for impeachment for it to pass. The opposition parties can almost reach that figure themselves - so Yoon's fate will come down to only eight votes.

Tessa Wong & Jake Kwon
reporting from Seoul

Throughout the rally various speakers have taken to the stage to give impassioned speeches. A top union leader has just finished speaking.

"We must wipe out the traitors. If the impeachment vote fails, all 1.5 million members of our union will run straight to the presidential office," he says.

"The traitors will be judged by the sharpened blade of the people!"

The national federation of unions called a general strike earlier this week in protest of Yoon. Metal industry workers and railway workers are among those who have refused to go to work.

Tessa Wong
reporting from Seoul

South Korea has a rich history of protest songs, and they are on full display here at the rally.

One is a tune that sounds like a children's song, with kids singing "South Korea is a democratic republic" to a catchy, repetitive tune.

Another is a stirring marching anthem called A March Song for You (the country).

Now the crowd is singing the Korean version of Do You Hear the People Sing, from the musical Les Misérables. It's a song that's become a popular protest anthem in Asia in recent years, most notably during the Hong Kong 2019 protests.

For days, Korean celebrities have mostly remained silent on the president's martial law declaration and its aftermath.

But today, 2,518 movie industry professionals and 77 film organisations in the country issued a joint letter asking the president to be "suspended and arrested".

Some big names are among them, including Bong Joon-ho, director of Oscar-winning movie Parasite, and Son Ye-jin, actress from the popular Netflix show Crash Landing On You.

"If impeachment is the fastest way, then we should choose impeachment, and if there is another way to remove him from office, we should find the fastest way," they said in the statement.

"To the filmmakers of the Republic of Korea, Yoon Suk Yeol is no longer the president. He is merely a criminal caught in the act of insurrection," they added.

"Quickly suspend Yoon from his duties as president, dismiss and arrest him."

Image source, Getty Images

The impeachment motion, if passed, would mean Yoon is temporarily suspended from his duties. The prime minister would fill the gap until a formal impeachment trial can be held.

Two thirds of the parliament - 200 people - need to vote in favour of the motion for it to pass.

The opposition parties moving the motion almost have the numbers themselves - they only need eight votes from the People Power Party (PPP), which is the group the president belongs to.

The PPP said they'll officially oppose the impeachment motion, but after more information about Tuesday's martial law declaration came to light, their leader said Yoon is a danger to the public and some members have indicated they are open to supporting it.

After President Yoon's TV address today, South Korea's ruling party leader Han Dong-hoon, who said yesterday that he thinks the president should be suspended immediately, held an emergency meeting with Prime Minister Han Duck-soo, who was appointed by Yoon.

If Yoon gets impeached this afternoon, the prime minister will step in as acting president.

The two discussed the ongoing political crisis and measures to stabilise the government, Korean media reports.

During the meeting, Han Dong-hoon urged the prime minister to handle the economic challenges and national affairs "with care and security" so as to not cause the people to panic. The prime minister said he would work closely with his party for these matters.

Image source, EPA

Click play below to hear what the president had to say in his address this morning - his first public comments since Tuesday night's short-lived martial law declaration.

Jean Mackenzie
reporting from Seoul

We’re inside the grounds of the National Assembly. Protesters are pressed right up at the gates, looking in, waiting eagerly for the impeachment vote in an hour’s time.

"The President’s party must vote to impeach," they chant.

This will be the decider today. The opposition needs eight members of the ruling party to vote with them.

We don’t know yet if they have those votes, or whether President Yoon has reached a deal with his party to keep them loyal.

We are once again seeing South Korea's robust protest culture take off across the capital Seoul.

Huge crowds numbering in the tens of thousands have assembled outside the National Assembly and along main roads in Yeouido, where the parliament building is located.

Demonstrators are holding placards calling for President Yoon's arrest and the safeguarding of democracy.

Metro stations leading to the National Assembly are packed, according to people on social media.

Image source, BBC / Tessa Wong

Image source, BBC / Jean Mackenzie

Image source, BBC / Tessa Wong

Laura Bicker
reporting from Seoul

Image source, EPA

A few pro-Yoon supporters have gathered in a corner next to the main protest outside the National Assembly.

Surrounded by lines of police, they are calling for the arrest of opposition leader Lee Jae-myung, rather than the president.

The two sides are shouting at one another.

It is clear, though, that the overwhelming majority of people who’ve turned out today - tens of thousands from across the country - are calling for the impeachment of President Yoon.

Tessa Wong
reporting from Seoul

I've reached the main thoroughfare leading to the National Assembly and it's completely packed with tens of thousands of people chanting "Impeach, impeach!"

On stage, an acapella group sings joyful tunes. Then a pianist starts up and plays a stirring emotional song resembling Edelweiss.

Protesters sitting cross legged on the road sway along, waving their placards.

On the side streets, vendors have set up food carts while a street performer wearing a Yoon mask and an inflatable suit dances next to a blaring boombox.

Image source, BBC / Tessa Wong