South Korea President Yoon poses 'great danger' — ruling party chief

South Korean President Yoon Suk-yeol could put citizens in "great danger" if he is not suspended, the head of the ruling party has said.

"(If) President Yoon continues to hold the office of the presidency, there is a significant risk that extreme actions similar to the martial law declaration could be repeated, which could put the Republic of Korea and its citizens in great danger," said People Power Party chief Han Dong-hoon on Friday.

Han said Yoon needs to be removed from authority for the safety of the country for trying to impose martial law, but stopped short of urging members to vote for impeachment.

Credible evidence suggests that Yoon ordered the arrest of key politicians on the night he declared martial law this week, the head of the ruling party added.

"It was confirmed last night (Thursday) through credible evidence that on the day martial law was declared, President Yoon Suk-yeol instructed the chief of the Counterintelligence Command, his junior from university, to arrest key politicians, (labelling) them as anti-state forces, and mobilised intelligence agencies to arrest them."

Yoon shocked the nation and his own ruling party on Tuesday when he announced he was imposing martial law in order to root out "anti-state forces" and overcome obstructionist political opponents.

He reversed course about six hours later after Parliament, including some members of his party, voted to oppose the decree.

Impeachment vote

The main opposition Democratic Party has scheduled an impeachment vote for Saturday evening, and the national police have launched an investigation into Yoon on claims of insurrection filed by an opposition party and activists.

On Thursday, the ruling party said it was against impeachment, but Han suggested that stance may be shifting in light of "credible evidence" that Yoon had intended to arrest and detain political leaders at Gwacheon, just south of Seoul.

"I said yesterday that I would try not to pass this impeachment in order to prevent damage to the people and supporters caused by the unprepared chaos, but I believe that President Yoon Suk-yeol's immediate suspension of office is necessary to protect the Republic of Korea and its people in light of the newly revealed facts," Han said.

He did not explicitly call for impeachment or respond to reporters when asked for clarification.

Democratic Party leader Lee Jae-myung said the declaration of martial law was a rebellion waged by the president in order to maintain or extend his power.

"It's an act of insurrection," he said. "It's a pro-military coup."