National Assembly Speaker Woo Won-shik declares the passage of an impeachment motion against acting President Han Duck-soo during a plenary session at the National Assembly in Seoul, Friday. Yonhap

Acting President and Prime Minister Han Duck-soo was impeached by the National Assembly, Friday, in an unprecedented parliamentary move to oust the nation's interim leadership amid a deepening political crisis.

Han's dismissal comes less than two weeks after he assumed the acting presidency following President Yoon Suk Yeol's impeachment by the Assembly on Dec. 14 for his botched martial law imposition. This marks the first time in Korean history that both the president and prime minister — the top two figures in the government hierarchy — have been simultaneously suspended from their duties.

The impeachment motion against Han, submitted by the main opposition Democratic Party of Korea (DPK) on Thursday, was approved in a plenary session with 192 of the 300-seat Assembly voting in favor.

While the vote was unanimous, it appeared to be railroaded by opposition lawmakers, as the broader opposition bloc holds all 192 seats, while the ruling People Power Party (PPP) boycotted the vote.

The PPP, which holds the remaining 108 seats, did not participate in the vote, protesting against the Assembly speaker's decision regarding the quorum requirement of 151 votes. The rival parties had been at odds over the required voting threshold for the acting president's impeachment.

Acting President Han Duck-soo arrives at a briefing room at Government Complex Seoul to give a public address, Thursday. Joint Press Corps

Under the Constitution, the passage of an impeachment motion against the prime minister requires a majority of the 300-seat Assembly, or 151 votes. Impeaching a president, however, requires the approval of at least two-thirds of the total Assembly members, or 200 votes in favor.

The DPK argued that Han, who is technically serving as prime minister, falls under the majority-vote requirement, while the PPP contended that Han should be treated as a president.

Assembly Speaker Woo Won-sik determined that Han's impeachment requires 151 ballots.

"This is an impeachment motion against Prime Minister Han Duck-soo. In accordance with Article 65 Clause 2 of the Constitution, it will be approved by a majority of total members. While there are differing views on the quorum, the subject of this impeachment motion is the prime minister, who is temporarily exercising presidential power," Woo said before the voting.

PPP members strongly protested, chanting slogans such as “the speaker should resign,” and “abuse of power." They left the Chamber as the vote count began.

Ruling People Power Party lawmakers protest during a plenary session at the National Assembly, Friday, on Speaker Woo Won-sik's decision on the required quorum of 151 votes for the passage of the impeachment motion against Acting President Han Duck-soo. Yonhap

Following the passage of the impeachment motion, the Constitutional Court has 180 days to decide whether to uphold Han's impeachment. In the meantime, Han's duties will be suspended, and Deputy Prime Minister Choi Sang-mok, who also serves as minister of economy and finance, will assume interim leadership.

"I respect the decision of the National Assembly, and in order to prevent further confusion and uncertainties, my duties will be suspended in accordance with relevant laws, while I will wait for the swift and wise decision of the Constitutional Court," Han said in a statement, shortly after his impeachment motion was passed.

The DPK filed the impeachment motion, Thursday, shortly after Han delayed the appointment of three Constitutional Court justice nominees who had won parliamentary approval.

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

The PPP has countered that Han, as acting president, does not have the authority to appoint justices until Yoon is formally impeached.

In a televised briefing on Thursday, Han stated that he would not approve the appointments until the ruling and opposition blocs reached an agreement on the matter.

The DPK also argued that the prime minister deserved impeachment for additional reasons, including his veto of special probe bills targeting the presidential couple, his alleged involvement in Yoon's botched martial law imposition, and his attempt earlier this month to establish a power-sharing arrangement with then-PPP leader Han Dong-hoon. The party claimed that these actions lacked legal grounds.

Rep. Lee Jae-myung, chairman of the main opposition Democratic Party of Korea, speaks during a press conference at the National Assembly in Seoul, Friday. Yonhap

DPK leader Rep. Lee Jae-myung described Han's impeachment as part of the party's efforts to dismantle what he referred to as “rebellion forces” linked to Yoon's martial law fallout.

“We will mobilize all resources and fulfill our historical responsibility until Yoon Suk Yeol is removed from office, his loyalist forces are eradicated, and the rebellion is fully suppressed,” Lee said during a briefing, hours before the impeachment vote.

The PPP criticized the opposition's move, calling the DPK “a serial impeachment offender.”

“This is already the 29th impeachment motion under the incumbent administration,” said PPP acting leader Rep. Kweon Seong-dong, questioning whether other Cabinet members would also face impeachment.

The governing party filed a complaint to the Constitutional Court against the Assembly speaker shortly after the motion was passed, claiming that Han's impeachment lacks legal basis.

"Despite the fact that the prime minister holds the role of acting president, his failure to apply the quorum threshold for the president is a major violation of the Constitution," the party said in a statement.

Deputy Prime Minister and Economy and Finance Minister Choi Sang-mok arrives at a briefing room at Government Complex Seoul to give a public address, Friday. Yonhap

Following Han's impeachment, Choi, the deputy prime minister, will assume the role of acting president.

However, it remains uncertain whether Choi, a seasoned economist who also serves as finance minister, will cooperate with the opposition parties in appointing Constitutional Court justices. It is also unclear how active he will be in exercising power in this unprecedented situation, where leadership has passed to the No. 3 figure in the government hierarchy.

"Minimizing the chaos in state affairs is the most urgent task right now. The government will put all of its efforts into maintaining robust security, a stable economy, and law and order, so that the safety of the nation and people's daily lives are not disrupted," Choi said in a public address, following Han's suspension of duty.

Before the parliamentary vote on Han's impeachment, Choi had requested the DPK to reconsider its move, expressing concerns that ousting the acting president would deal a heavy blow to the nation's economy.

“The absence of a control tower for state affairs will deal a severe blow to Korea's credibility, security, the economy and continuity of governance, as already evident in the sharp weakening of the won against the dollar,” Choi said during a press briefing.