South Korea's ruling party leader Thursday called for supporting impeachment against President Yoon Suk-yeol as its party stance, terming it as the only solution to the chaos caused by Yoon's martial law declaration.

The remarks by Han Dong-hoon, chief of Yoon's own People Power Party, came after the president delivered a televised address to the nation in which he justified his hugely controversial martial law decision.

Speaking to reporters, Han confirmed Yoon's unwillingness to resign early and said the president should immediately be excluded from state administration, including the right to command the military.

He said those involved in the unconstitutional and illegal declaration of martial law, including Yoon, should be strongly punished.

Han called on his party's lawmakers to vote on Yoon's impeachment based on their own "conviction."

"We must stop further confusion. There is only one effective method now," he said. "In the next (impeachment motion) vote, our party's lawmakers should enter the assembly hall and take part in the vote based on their own conviction and conscience."

The People Power Party had initially refused to back impeachment, hoping Yoon would resign from office instead. But its leadership said attempts to persuade Yoon had made no progress.

The opposition parties submitted a motion to impeach Yoon last week, but it was scrapped last Saturday as People Power Party lawmakers boycotted it.

The opposition camp planned to submit an impeachment motion again later in the day and put it up for a vote Saturday.