South Korean lawmakers impeach acting President Han Duck-soo

South Korean lawmakers impeached acting president Han Duck-soo on Friday, sinking the country deeper into a political crisis triggered by his predecessor's martial law declaration that shocked the world.

Han had taken over just two weeks ago from President Yoon Suk Yeol, who was suspended following a parliament vote over his move to impose martial law on December 3.

However, opposition MPs have now also stripped Han -- who was also prime minister -- of his presidential duties, arguing that he had refused demands to complete Yoon's impeachment process and to bring him to justice.

"I announce that Prime Minister Han Duck-soo's impeachment motion has passed. Out of the 192 lawmakers who voted, 192 voted to impeach," said National Assembly Speaker Woo Won-shik.

The vote was passed in chaotic scenes as the Han and Yoon's ruling People's Power Party (PPP) lawmakers protested in parliament after Woo said only a simple majority was required for the impeachment to pass.

PPP lawmakers began chanting angrily, with many MPs rushing towards Woo, demanding that he resign. They did not take part in the vote.

Friday's was the second impeachment of a South Korean head of state in just two weeks, adding to the turmoil of the country's dynamic political landscape.

It was also South Korea's first impeachment of an acting president.

PPP leader Kweon Seong-dong said after the vote that Han "must continue to lead state affairs without yielding to the opposition's passage of the impeachment motion".

However, Han said in a statement after the vote that he "respects the parliament's decision" and would wait for the Constitutional Court's subsequent decision whether to uphold it.

Finance Minister Choi Sang-mok, who stepped in as South Korea's new acting president, pledged to do all to end the political turmoil gripping his country.

"Minimizing governmental turmoil is of utmost importance at this moment," Choi said in an address shortly after his appointment as acting leader, adding that "the government will also dedicate all its efforts to overcoming this period of turmoil."

Amid the ongoing crisis, South Korea's won touched a 16-year low against the US dollar on Friday, faring worse than in the immediate aftermath of Yoon's martial law declaration, which sent the currency sliding to a two-year low against the greenback.

- 'True colors' -

At the heart of the current row is the composition of the Constitutional Court, which will decide whether to uphold parliament's decision to impeach Yoon, and now Han as well.

The court is currently short of three judges. While it can go ahead with its six members on the bench, a single dissenting vote would reinstate Yoon.

The opposition wanted Han to approve three more nominees to fill the nine-member bench, which he had refused to do, leaving both sides in deadlock.

Han's refusal to formally appoint the three judges "revealed his true colors", said Democratic Party lawmaker Jo Seoung-lae.

The refusal "is a direct challenge to the Constitution and the law", said Jo. They sought to impeach Han to "restore constitutional order and stabilize state affairs".

The opposition said in its impeachment motion that Han was "intentionally avoiding the special investigation to probe those involved in the insurrection and has clearly stated his intention to reject the appointments of three Constitutional Court judges".

Such actions, it said, were "in violation of a public official's duty to uphold the law... and serve the public".

Han had said he wanted his PPP and the opposition to reach a compromise on the nominees.

"The consistent principle embedded in our constitution and laws is to refrain from exercising significant exclusive presidential powers, including the appointment of constitutional institutions," Han argued.

"A consensus between the ruling and opposition parties in the National Assembly, representing the people, must first be reached," the 75-year-old career bureaucrat said.

The Constitutional Court held its first preliminary hearing on the validity of Yoon's impeachment on Friday despite the latest controversy, with the suspended president's legal team attending.

Separately, police said they had begun a raid on a presidential safe house and were collecting footage from nearby security cameras as part of the martial law probe.

© Agence France-Presse