Opposition party leader Han Dong-hoon speaks during a press conference at the National Assembly, in Seoul, Dec. 16. Yonhap

The leader of the ruling People Power Party (PPP) said Monday he is stepping down amid growing internal strife following the National Assembly's vote to impeach President Yoon Suk Yeol.

PPP leader Han Dong-hoon made the announcement during a press conference after an impeachment motion against Yoon was passed 204-85 on Saturday over his botched imposition of martial law on Dec. 3.

The results showed 12 PPP lawmakers likely broke from their party line to vote in favor of impeachment. Han expressed support for Yoon's impeachment Thursday despite his earlier calls for the president's "orderly" exit.

"I am stepping down as the leader of the People Power Party," Han said. "It has become impossible to carry out my duties as party chief due to the collapse of the party's Supreme Council."

Han apologized to all those who suffered from the martial law chaos and Yoon's impeachment but said he has "no regrets" over his decision to support the impeachment.

"Even if the martial law was imposed by a president from our party, being seen as defending the illegal martial law that mobilizes the military goes against the conservative values we stand for, the great country and its people -- who have achieved industrialization and democratization at the same time -- and the splendid achievements of our party," he said.

Han, however, stressed that even if the martial law declaration was wrong, it "does not in any way justify the rampant actions and alleged crimes" of the main opposition Democratic Party and its leader Lee Jae-myung.

"The countdown for Lee's trial goes on," he said.

Han had initially vowed to continue his duties but appears to have shifted his stance amid mounting pressure to step down after all five elected members of the PPP's Supreme Council, including two considered to be closely aligned with Han, expressed their intent to resign.

Newly elected floor leader Kweon Seong-dong will become the acting head of the conservative party. Kwon has the authority to appoint the head of an emergency leadership committee of the party.

Han, who was elected in July, had been considered one of Yoon's closest confidants from their time as prosecutors, before their relations ultimately soured over a number of politically sensitive issues, including how to handle allegations that first lady Kim Keon Hee received a luxury bag as a gift in 2022. (Yonhap)