South Korean lawmakers have called for the impeachment of the president after he declared martial law only to reverse the move hours later, triggering the biggest political crisis the country has faced in decades.

The surprise declaration late on Tuesday ignited a standoff with parliament which rejected President Yoon Suk Yeol’s attempt to ban political activity and censor the media.

After his earlier shock announcement, troops had entered the National Assembly building as police and protesters clashed outside. Lawmakers at one point used fire extinguishers to prevent troops from entering parliament.

The Swedish prime minister announced on Wednesday he has postponed his scheduled visit to South Korea this week.

Ulf Kristersson had been scheduled to hold a summit meeting with Mr Yoon.

A coalition of lawmakers from opposition parties said they planned to propose a bill to impeach Mr Yoon on Wednesday, which should be voted on within 72 hours.

“The parliament should focus on immediately suspending the president’s business to pass an impeachment bill soonest,” Hwang Un-ha, an MP in the coalition, told reporters.

Mr Yoon told the nation in a TV address that martial law was needed to defend the country from nuclear-armed North Korea and pro-North anti-state forces, and protect its free constitutional order, although he cited no specific threats.

Within hours, South Korea’s parliament, with 190 of its 300 members present, unanimously passed a motion requiring martial law be lifted, including all 18 members present from the president’s party.

The president then rescinded the declaration.

Why was martial law declared in South Korea?

Protesters outside the National Assembly parliament shouted and clapped, chanting “we won”.

South Korea’s largest union coalition, the Korean Confederation of Trade Unions, said thousands of its members would strike until Mr Yoon resigned and will hold a rally in Seoul.

Several other protests are expected, including near the National Assembly where thousands of people gathered late on Tuesday to call to block Mr Yoon’s order – and then demand his arrest and resignation.

South Korean stocks opened down around 2% on Wednesday, while the won steadied to trade around 1,418 to the dollar, having plunged to a two-year low.

‘He cannot avoid treason charges’

The main opposition Democratic Party (DP) has called for Mr Yoon, who has been in office for two years, to resign or face impeachment.

“Even if martial law is lifted, he cannot avoid treason charges,” a senior DP member of parliament, Park Chan-dae, said.

“It was clearly revealed to the entire nation that President Yoon could no longer run the country normally. He should step down.”

The National Assembly can impeach the president if more than two-thirds of lawmakers vote for it. A trial is then held by the constitutional court, which can confirm it with a vote by six of the nine justices.

Mr Yoon’s party controls 108 seats in the 300-member legislature.

“South Korea as a nation dodged a bullet, but President Yoon may have shot himself in the foot,” said Danny Russel, vice president of the Asia Society Policy Institute think tank in the United States.

The country has been a democracy since the 1980s and is a US ally and major Asian economy.

The crisis caused international alarm. US Secretary of State Antony Blinken said he welcomed Mr Yoon’s decision to rescind the martial law declaration.

“We continue to expect political disagreements to be resolved peacefully and in accordance with the rule of law,” Mr Blinken said in a statement.

South Korea’s previous period of martial law was in October 1979.

South Korea’s president has said he will lift the emergency martial law order he had declared just hours earlier.

Yoon Suk Yeol’s decision comes after parliament voted to block the order, with the speaker of the National Assembly, Woo Won Shik, declaring it “invalid” and saying politicians would “protect democracy with the people”.

The president, who appears likely to be impeached over his actions, had said in a TV address on Tuesday night he was putting the military in temporary charge to defend the constitutional order and “eradicate the despicable pro-North Korean anti-state forces”.

But in a U-turn, Mr Yoon said martial law command forces have withdrawn and a cabinet meeting will be held as soon as possible.

In the end martial was in effect for about six hours.

South Korea martial law: Follow latest updates

After his earlier shock announcement, troops had entered the National Assembly building as police and protesters clashed outside and helicopters, likely to be from the military, flew overhead.

Staff barricaded the doors of the building, in the capital Seoul, to try to stop the soldiers entering.

Inside however, politicians were able to hold a vote and unanimously decided by 190-0 to block the president’s declaration.

According to the law, martial law must be lifted if the assembly votes against it – and police and soldiers were later seen leaving parliament.

Lee Jae-myung, who heads the opposition liberal Democratic Party, which holds the majority in the 300-seat parliament, said anyone acting under the orders of Mr Yoon or the martial law edict was now “breaking the law”.

Despite the vote, the defence ministry told reporters it would uphold the order “until the president lifts [it]”.

The president had said in his earlier TV address that martial law was necessary to protect “from the threat of North Korean communist forces, to eradicate the despicable pro-North Korean anti-state forces that are plundering the freedom and happiness of our people, and to protect the free constitutional order”.

The declaration was the first since the country’s democratisation in 1987.

UK ‘deeply concerned’

Following the announcement, the military said parliament and other political gatherings were suspended and the media was under its control, reported Yonhap news agency.

US deputy secretary of state Kurt Campbell said the White House was watching with “grave concern” while Britain’s minister for the Indo-Pacific, Catherine West, said the UK was “deeply concerned”.

She advised Britons to monitor and follow Foreign Office advice and said its Seoul embassy was “in touch with the Korean authorities”.

“We call for a peaceful resolution to the situation, in accordance with the law and the constitution of the Republic of Korea,” said Ms West.

South Korea’s democracy was tested – and its people rose to the occasion

Dominic Waghorn

International affairs editor

@DominicWaghorn

People power appears to have prevailed in South Korea, defanging a last ditch attempt by a beleaguered lame duck president to declare martial law.

President Yoon’s gambit has backfired spectacularly.

His bombshell announcement late at night led not to a swift imposition of military rule, but instead galvanised popular opposition.

Protesters raced to the country’s parliament allowing MPs inside to vote to overturn the rogue president’s martial law plan.

There was a tense standoff between protesters and police but no violence.

The swift response seized the initiative from the president who was left with little option but to backdown. He now faces investigation by his political opponents along with his minister for national defence who they say was also complicit.

President Yoon may be familiar to some from a viral video showing him crooning American Pie in a soft soothing baritone in an impromptu performance in the White House.

He was not a conventional political performer and has been embroiled in deepening political difficulty since his party lost its parliamentary majority in this year’s elections.

He is now in a world of political pain as he prepares to pay the price for his extraordinarily rash move.

South Korea itself emerges from the episode with less to worry about.

It may have been unnerving, but the constitution, the parliament and the people appear to have weathered the storm and risen to the moment.

South Korea’s democracy has been tested and proven resilient in an unprecedentedly challenging few hours.

Scandals and a government in crisis

Since taking office in 2022, President Yoon has struggled to push his agenda against an opposition-controlled parliament.

His conservative People Power Party has been in a deadlock with the liberal Democratic Party over next year’s budget.

Ministers protested the move on Monday by the Democratic Party to slash more than four trillion won (approximately £2.1bn) from the government’s proposal.

Mr Yoon said that action undermines the essential functioning of government administration.

The president has also dismissed calls for independent investigations into scandals involving his wife and top officials, which has drawn criticism from his political rivals.

Security and defence analyst Professor Michael Clarke told Sky News the government in South Korea has been in “crisis” for a couple of years.

“Yoon has been leading a minority government for some time, against him the Democratic Party have just frustrated whatever he has tried to do,” Clarke said.

“He has decided to get ahead of his opposition by creating this move.

“The last thing that liberal democracy needs at the moment is one of the democracies of Asia turning into a short-term dictatorship, so I think this is only a short-term parliamentary manoeuvre, but it may turn out to be more.”

Martial law is typically temporary, but can continue indefinitely. It is most often declared in times of war and/or emergencies such as civil unrest and natural disasters.

South Korea’s previous period of martial law was in October 1979.

South Korean President Yoon Suk Yeol has lifted martial law, which he implemented hours earlier in a move that shocked MPs, the public and international allies.

In a national address, the president said: “I have accepted the decision made by the National Assembly to dissolve and lift the martial law.”

MPs, including members of his own ruling party, voted to block the declaration as protesters clashed with soldiers and police after the martial law ruling.

But what is martial law, and why did the president introduce it?

What is martial law?

It enacts temporary rule by the military and is usually invoked in times of war, rebellion or natural disaster.

When martial law is in effect, the military commander has unlimited authority to make and enforce laws.

It suspends all existing laws – meaning there can be a suspension of normal civil rights and the use of military law on the civilian population.

The step is taken when the civilian authorities are deemed unable to function.

The surprise move was the first declaration of martial law since the country’s democratisation in 1987.

Martial law is typically temporary, but it can continue indefinitely. It is most often declared in times of war or emergencies such as civil unrest and natural disasters.

Recent examples of martial law being enforced include in Ukraine following Russia’s full-scale invasion.

Why did the president introduce it?

In his announcement on Tuesday night, Yoon Suk Yeol said it was critical for defending the country’s constitutional order.

“I declare martial law to protect the free Republic of Korea from the threat of North Korean communist forces, to eradicate the despicable pro-North Korean anti-state forces that are plundering the freedom and happiness of our people, and to protect the free constitutional order,” Mr Yoon said.

The move came after two years of Mr Yoon struggling to push his agendas through in an opposition-controlled parliament.

His conservative People Power Party has been in a deadlock with the liberal Democratic Party over next year’s budget bill.

Ministers protested against the move on Monday by the Democratic Party to slash more than four trillion won (approximately £2.1bn) from the government’s budget proposal.

South Korea martial law: Follow live updates

Mr Yoon said that action undermines the essential functioning of government administration.

The president has also dismissed calls for independent investigations into scandals involving his wife and top officials, drawing criticism from his political rivals.

Security and defence analyst Professor Michael Clarke told Sky News he believed the introduction of martial law was Mr Yoon’s attempt to thwart his political opponents.

“Yoon has been leading a minority government for some time, against him the Democratic Party have just frustrated whatever he has tried to do,” Clarke said.

“He has decided to get ahead of his opposition by creating this move.

“The last thing that liberal democracy needs at the moment is one of the democracies of Asia turning into a short-term dictatorship.”

What was the reaction?

Before the president lifted martial law, opposition leader Lee Jae-myung said the declaration of martial law was “unconstitutional” and called for the public to protest outside parliament.

The parliament, which is controlled by the opposition party, voted to block the president’s decision, which he reversed just a few hours later.

According to the law in South Korea, the government must lift martial law if the majority of the National Assembly demands it in a vote.

Live TV footage from earlier today showed South Korean parliament aides pushing back martial law forces, spraying fire extinguishers while the public and police clashed.