South Korean court begins Yoon impeachment trial

South Korea's constitutional court has kicked off proceedings over the impeachment of President Yoon Suk Yeol, who has been suspended from office over his failed bid to impose martial law.

Mr Yoon was removed by South Korea's parliament over his short-lived attempt to suspend civilian rule, which plunged the country into its worst political turmoil in years.

The Constitutional Court has around six months to determine whether to uphold the impeachment.

Fresh elections must be held within two months if he is removed. Prime Minister Han Duck-soo is serving as interim leader in Mr Yoon's stead.

A separate investigation into Mr Yoon and his inner circle over the 3 December martial law declaration has rumbled on as the turmoil deepened.

Mr Yoon remains under a travel ban while the probe is under way.

The prosecution said in a news release they had summoned Mr Yoon for questioning over the insurrection and abuse of power allegations "but he refused to comply".

Yoon 'ringleader'

The concurrent probe by a joint police, anti-corruption office and defence ministry team is also asking Mr Yoon to appear for questioning, Yonhap said.

They reportedly accuse Mr Yoon of being the "ringleader" of the martial law bid.

Vast protests against the former leader, with smaller rallies supporting him, have rocked the South Korean capital since his martial law decree.

The head of Mr Yoon's ruling People Power Party (PPP), who has not been linked to the martial law bid and expressed support for impeachment, has resigned.

"I sincerely apologise to all the people who have suffered due to the emergency martial law incident," Han Dong-hoon told a news conference in Seoul.

In declaring martial law, Mr Yoon vowed to "eliminate anti-state elements" and suggested the country's electoral system was vulnerable to outside interference.

Han Dong-hoon condemned "extremists such as election fraud conspiracy theorists" and warned "there will be no future for conservatism" if the party entertained those views.

"I wish for the well-being of our country," he added.

North Korea weighs in

Meanwhile the South Korean government has sought to project an air of business as usual.

Acting president Han Duck-soo held a call with US President Joe Biden, who underscored the strength of bilateral ties.

Mr Han has also ordered the military to "enhance vigilance" against North Korea, with which the South technically remains at war.

North Korean state media decried Mr Yoon as a "ringleader of rebellion", its first reaction to his impeachment.

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The state-run Korean Central News Agency said Mr Yoon had attempted to shift responsibility for the "foolish emergency martial law declaration" onto opposition parties.

"The investigation into puppet Yoon Suk Yeol, the ringleader of the rebellion, and his accomplices is under way," KCNA said.

"The puppet Constitutional Court will finally decide" on whether to remove Mr Yoon, it said.

North Korean state media often refers to the South's leaders and institutions as being a "puppet" of South Korea's treaty ally, the United States.

Relations between the two Koreas have been at one of their lowest points in years, with the North launching a flurry of ballistic missiles in violation of UN sanctions.