A majority of South Korea's parliament has voted to impeach acting president Han Duck-soo.
Prime Minister Han has been acting president since President Yoon Suk Yeol was impeached on 14 December over his short-lived imposition of martial law on 3 December, and his presidential powers were suspended.
After Mr Han's impeachment, Finance Minister Choi Sang-mok is next in line to assume the acting presidency, according to South Korean law.
Some 192 lawmakers voted to impeach Mr Han out of the 300-member parliament.
The main opposition Democratic Party (DP), which controls parliament, decided to impeach Mr Han after he did not immediately appoint three justices to fill vacancies at the Constitutional Court.
The parliament backed three nominees yesterday, but Mr Han said he would not formally appoint them unless there was bipartisan agreement on the appointments.
There has been disagreement between the ruling and opposition parties and some constitutional scholars over whether a simple majority or a two-thirds vote is needed to impeach the acting president.
However, parliament speaker Woo Won-shik, who is from the DP, said only a simple majority was needed to impeach Mr Han.
Ahead of the parliamentary session, opposition leader Lee Jae-myung accused Mr Han of "acting for insurrection".
"The only way to normalise the country is to swiftly root out all the insurrection forces," Mr Lee said in a fiery speech, adding the party was acting on the public order to eradicate those who have put the country at risk.
There had been overwhelming public support for Mr Yoon's removal, according to opinion polls conducted after his martial law attempt.
The South Korean won weakened to a fresh low of 1,486.7 per dollar, the weakest since March 2009, as analysts said there was little to reverse the negative sentiment stemming from the political uncertainty.
The vote to determine Mr Han's fate comes on the same day the Constitutional Court held its first hearing in a case reviewing whether to overturn the impeachment and reinstate Mr Yoon or remove him permanently from office. It has 180 days to reach a decision.
Speaking for the court in a preparatory hearing, Justice Cheong Hyung-sik said the court will move swiftly on the case considering its gravity, denying a request by Mr Yoon's lawyers for a postponement in proceedings to better prepare the case.
In the hearing that wrapped up under an hour, the court set the next hearing for 3 January.
The hearing follows weeks of defiance by Mr Yoon ignoring requests by the court to submit documents as well as summons by investigators in a separate criminal case over his martial law declaration.
Worst political crisis in decades
The events following the 3 December martial law declaration have plunged the country into its gravest political crisis since 1987, when widespread protests forced the ruling party of former military generals into accepting a constitutional amendment bringing in direct, popular vote to elect the president.
Mr Yoon shocked the country and the world with a late-night announcement on 3 December that he was imposing martial law to overcome political deadlock and root out "anti-state forces".
The military deployed special forces to the national assembly, the election commission, and the office of a liberal YouTube commentator.
It also issued orders banning activity by parliament and political parties, as well as calling for government control of the media.
But within hours, 190 lawmakers had defied the cordons of troops and police and voted against Mr Yoon's order. About six hours after his initial decree, the order was rescinded.
Mr Yoon and senior members of his administration also face criminal investigations for insurrection.
