The leader of South Korea's ruling People Power Party says President Yoon Suk-yeol will not take part in state affairs, including diplomacy, even while he is still in office.

Han Dong-hoon also vowed to promptly bring the situation back to normal, following the president's short-lived declaration of martial law.

PPP leader Han released a joint statement with Prime Minister Han Duck-soo on Sunday. It came after an impeachment motion against President Yoon Suk-yeol the day before failed due to a lack of voters.

The PPP leader said the majority of the public believes the president should step down, as he is unable to run the government normally for the remainder of his term.

He said he would ensure that the ongoing investigation into the martial law declaration is conducted rigorously without exception.

The prime minister offered an apology, saying he feels great responsibility. He added he will do all he can to stabilize the situation as early as possible.

Yoon said on Saturday he would leave it up to his party to decide how to fix the political situation, including his term.

On Sunday morning, prosecutors detained former Defense Minister Kim Yong-hyun, who allegedly advised Yoon to declare martial law.