SOUTH Korean police are investigating President Yoon Suk Yeol for alleged “insurrection” after his stunning but brief declaration of martial law, a senior police officer said today.

The investigation comes as trade unionists staged a general strike and parliamentarians move towards impeaching the president.

The head of the National Investigation Headquarters of the National Police Agency, Woo Jong Soo, told lawmakers that “the case has been assigned.”

Insurrection can carry the death penalty in South Korea.

Meanwhile President Yoon was still clinging to power today, with his party, the People Power Party, announcing they will oppose an opposition motion of impeachment which looks set to be taken on Saturday.

Mr Yoon suspended civilian rule late on Tuesday and deployed troops and helicopters to parliament only for lawmakers to vote down the measure and force him into a U-turn after a night of protests and drama.

The motion from the opposition said that President Yoon “gravely violated the constitution and the law.”

Even though the president’s own party has said that it opposes the impeachment, five of its members said today they were undecided about which way to vote.

At a press conference, the lawmakers — Kim Jae Sub, Kim Sang Wook, Kim So Hee, Kim Yae Ji and Woo Jae Jun — have called on President Yoon to make a national apology for his martial law declaration and said they had not yet decided to support the president.

The parliamentarians added that whatever they decided, they would vote together.

The impeachment motion needs 200 votes to pass. The opposition have 192 seats and would need at least eight of the 108 ruling party MPs to back their motion for it to pass.

Meanwhile, Hyundai’s 43,000 members of the country’s Metal Workers’ Union walked out today for the first of two four-hour strikes and vowed to launch a full strike on December 11 if the president does not step down or is not removed.

Workers from across South Korea also downed tools to demand the removal of President Yoon following the call for an indefinite general strike by the leaders of the 1.1 million-strong Korean Confederation of Trade Unions (KCTU).

The International Trade Union Confederation-Asia Pacific sent a message of support to the KCTU and the Federation of Korean Trade Unions and strongly condemned the imposition of martial law. 

A statement from the union federation said: “This anti-democratic action is a blatant attack on the constitutional order and a dangerous step towards dictatorship.”

A message from the European Public Services Unions said they were closely watching developments in South Korea and “stood together” with the unions taking action to defend democracy.