South Korea’s main opposition leader said it may be difficult to garner enough support from the ruling party to impeach President Yoon Suk Yeol this week over his declaration of martial law.

In an interview on Thursday, Democratic Party leader Lee Jae-myung said the situation remains in a "state of flux” ahead of a parliamentary vote set for the next few days on launching impeachment proceedings against Yoon. Whatever happens in the vote, he said he remains committed to removing the president.

While Lee’s party controls a majority in the legislative body, it needs a minimum of eight votes from Yoon’s People Power Party to move forward with the motion to oust the president.

"The problem is that while many of the ruling party lawmakers have the intention, they would need to go against the party line, which puts them in a bit of a difficult situation,” Lee said in his office at the National Assembly building in Seoul, where the late-night drama played out amid a standoff between troops, protesters and lawmakers earlier this week.

While members of Yoon’s party quickly voted with the opposition to reject the president’s martial law order earlier this week, PPP leader Han Dong-hoon said Thursday that he will push against the passage of the impeachment motion. Han said he had asked Yoon to leave the party, a move that would further isolate the embattled president.

Lee said his party will continue to seek Yoon’s ouster even if he survives the initial impeachment vote. The DP has accused the president of treason following the failed bid to impose martial law, a move that blindsided the nation, his own party and allies like the U.S.

"He will be impeached — the only question is whether he will be ousted the day after tomorrow, a week after, or a month or three later,” Lee said.

Recalling the events of Tuesday night, Lee said he jumped over a 1-meter fence to get inside the National Assembly as it was blocked by scores of armed troops after the martial law decree. After lawmakers voted down the measure, Yoon rescinded the order around 4:30 a.m. local time on Wednesday.

"Yoon made a dent to South Korea’s reputation through this abnormal and incomprehensible behavior,” Lee said.

While both Lee and Han are among the leading candidates to replace Yoon, should he step down, the DP leader is facing the risk of being excluded from political life after a court convicted him of violating election laws in November.

Lee, 60, narrowly lost to Yoon in the 2022 presidential election, but his landslide win for the Democratic Party in April parliamentary elections gave him renewed momentum.

Han’s move to rally PPP support against the impeachment motion may help him show that the party is still faithful to its conservative support while distancing itself from the president.

"I am in no way defending the president’s unconstitutional martial law. I have been and will continue to be with the people in their outrage and patriotism over this situation,” Han said at a meeting with senior party officials.

The opposition is now targeting Saturday for the parliamentary vote on the impeachment motion, Democratic Party officials said.

It was not immediately clear how the ruling party would prevent its members from defying the party policy and joining the opposition in the anonymous vote. Some opposition lawmakers said the ruling party could boycott the session en masse.

"Even if the result of a temporary vote goes against the will of the people under the current situation, I think the vote result can change next time if individual members of the parliament are pressured heavily by public opinion,” Lee said.

Earlier in the day Yoon appeared to dig in as he bids to remain as president. He named Choi Byung-hyuk, ambassador to Saudi Arabia, to replace Kim Yong-hyun as the defense minister, the presidential office said in a statement.

Kim ordered troops to the National Assembly where lawmakers were assembling to vote down the martial law decree, according to Yonhap.