South Korea’s ruling party chief has called for President Yoon Suk Yeol to “suspend his duties soon”, saying that citizens could be in “great danger” if he remained in power.

Han Doong-hoon, the leader of the People Power Party (PPP), added that his party had received “credible evidence” that Yoon had ordered the arrest of key politicians on “anti-state charges”.

His comments, made at an emergency party meeting on Friday, appear to be a departure from his earlier stand that his party would block the opposition’s impeachment motion, which is due to be put to the vote on Saturday.

The opposition needs at least eight ruling party MPs to back the impeachment motion for it to succeed.

Han expressed concerns that “extreme actions” – such as the martial law declaration on Tueaday – could be repeated if Yoon remains in office.

“[These will] putting the Republic of Korea and its people at great risk,” he said.

He added that his party had learned about plans to jail the arrested politicians in a detention centre in Gwacheon, a city south of Seoul.

Meanwhile, ruling party MP Cho Kyung-tae became the first ruling party MP to publicly voice his support for Yoon’s impeachment.

“The choice is between standing on the side of the people by suspending the president’s duties or becoming an ally of the forces that imposed martial law is a matter for politicians to judge,” Cho said.

“I hope that all the politicians of the People’s Power will stand on the side of the people,” he said.

Additional reporting by Hosu Lee in Seoul