Members of the main opposition Democratic Party of Korea, including Chairman Rep. Lee Jae-myung, front row third from left, calls for acting President Han Duck-soo to promulgate special probe bills targeting President Yoon Suk Yeol and first lady Kim Keon Hee, during a party meeting at the National Assembly in Seoul, Tuesday. Yonhap

The main opposition Democratic Party of Korea (DPK) said Tuesday that it will wait until Thursday before submitting an impeachment motion against acting President Han Duck-soo, after he refused to meet the party's demand to promulgate special investigation bills targeting President Yoon Suk Yeol and first lady Kim Keon Hee by Christmas Eve.

The DPK issued the two-day ultimatum, saying that it will see whether Han immediately appoints three Constitutional Court justices before making its final decision on whether to oust him.

The opposition has been pushing for the swift appointment of justices to fill three vacancies on the nine-member Constitutional Court, as a full bench would increase the likelihood of endorsing the impeachment of the president.

"We had originally planned to submit the impeachment motion at 5:30 p.m. today, but decided to wait and see if the acting president immediately appoints three Constitutional Court justices when their nominations are confirmed during the plenary session on Thurday," said DPK floor leader Rep. Park Chan-dae.

Park said his party has "decided to wait with patience, taking into account the public's sentiment."

His remarks came just about an hour after the party's initial announcement that it will submit an impeachment motion later in the day and put it up for a vote on Friday.

The sudden change in plans seem to reflect the party's concern that immediately moving forward with Han's impeachment could have negative consequences. The fact that Han, as acting president, has the authority to appoint Constitutional Court justices — a key issue for the DPK — appears to have prompted the U-turn.

Rep. Park Chan-dae, center, floor leader of the main opposition Democratic Party of Korea, speaks during a meeting at the National Assembly in Seoul, Tuesday. Yonhap

If Han is impeached, it would mark the first time in Korean history that both the president and the prime minister — the top two figures in the government hierarchy — have been ousted by parliament.

Han has been serving as acting president after the National Assembly passed a motion to impeach Yoon on Dec. 14 over his botched martial law.

The DPK claimed that Han deserves to be impeached not only because he failed to fulfill his duties as acting president by overlooking the special probe bills, but also because he participated in two Cabinet meetings just before and after Yoon's Dec. 3 martial law declaration as prime minister, and thus was also responsible for the chaos.

"We will immediately initiate an impeachment process against Han," Park said during a party meeting earlier in the day, shortly after a Cabinet meeting convened by the acting president ended without reviewing the two special probe bills.

"He has made it clear at today's Cabinet meeting that he will not promulgate the special investigation bills. This move can only be interpreted as an attempt to delay the probe and prolong the insurrection."

The opposition party, which holds a majority of seats in the National Assembly, has threatened to impeach Han if he fails to promulgate two special probe bills: one targeting first lady Kim Keon Hee's corruption allegations, and another for Yoon's martial law fiasco. The opposition bloc railroaded both bills at the Assembly on Dec. 12.

While Yoon had vetoed dozens of DPK-led bills, including those targeting his wife, the opposition bloc has claimed, after the Assembly's impeachment vote, that the acting president should not exercise the veto rights, especially for the bills targeting the presidential couple.

The DPK had issued an ultimatum, Sunday, stating that Han will "bear responsibility" if he fails to make a decision by Christmas Eve.

Acting President Han Duck-soo speaks during a Cabinet meeting at Government Complex Seoul, Tuesday. Joint Press Corps

But Han skipped the review of both bills, missing the deadline set by the DPK. He said that the special probe bills require further deliberation, as certain clauses do not align with the Constitution.

"It is necessary for the ruling and opposition parties to deliberate together to wisely address contentious issues where legal interpretations and political views clash, such as the handling of the special counsel bill or the appointment of Constitutional Court justices," the acting president said during the Cabinet meeting.

"I believe the first step should be for both sides to negotiate a compromise that will ensure that the appointment of a special counsel is carried out in strict adherence to the Constitution and the law, so that the majority of the public can find it convincing," he added.

By skipping the review at Tuesday's Cabinet meeting, Han delayed the decision by a week. He now faces the deadline of Jan. 1 to decide whether to promulgate or veto the bills, in order to meet the two-week legal deadline for bills approved by parliament.

The prime minister's office said that the bills can be discussed at a soon-to-be launched consultative body between the rival parties and the government, which is set to hold an inaugural meeting on Wednesday.

However, the DPK appears skeptical about even launching the consultative body after Han failed to review the bills.

"There are serious concerns about the consultative body's potential to succeed, considering Han's remarks today," the party's spokesperson Rep.Yoon Jong-geun told reporters.

Han's office expressed regret over the DPK's move.

"The government has always made decisions based on the Constitution and laws, with a focus on the future of the nation, and we will continue to do so ... As a government official, I deeply regret the DPK's remarks and hope they will be more thoughtful in the future," a senior official at the prime minister's office said.

People stage a rally calling for acting President Han Duck-soo to approve special probe bills as they march toward Han's official residence in Jongno District, Seoul, Friday. Yonhap

While the main opposition pushes ahead with Han's impeachment, controversy continues over how many votes are required to approve an impeachment motion against an acting president.

Under the Constitution, the passage of an impeachment motion against the prime minister requires a majority of the 300-seat Assembly, or 151 votes. This means that the DPK, with its 170 seats, has enough votes on its own to proceed with Han's impeachment.

Impeaching a president, however, requires the approval of at least two-thirds of the total Assembly members, or 200 votes in favor. To reach this figure, the opposition bloc, which holds 192 seats altogether, will need splinter votes from the ruling People Power Party (PPP).

According to DPK Rep. Kim Han-kyu's office, the National Assembly Research Service viewed that the rule for the prime minister should apply for the acting president as well.

"If the causes for impeachment arise while he has been performing his duty as prime minister, before assuming the role of acting president, the voting rules for impeaching a prime minister should be applied," the researchers said in a statement sent to Kim.

On the other hand, the governing party argued that 200 votes are needed to impeach Han.

"As the acting president holds the same position as the president, his impeachment requires the approval of at least two-thirds of the total members of the Assembly," PPP acting leader Rep. Kweon Seong-dong said Monday.

If Han is ousted, Deputy Prime Minister and Economy and Finance Minister Choi Sang-mok will step in as interim leader. This scenario may intensify the ongoing political turmoil, as Choi has already expressed his willingness to resign following the martial law fallout.