SEOUL -- South Korea's main opposition Democratic Party will immediately launch impeachment proceedings against Prime Minister Han Duck-soo who became the acting president following President Yoon Suk-yeol's impeachment over his botched martial law imposition, the party's floor leader said Tuesday.

Park Chan-dae, floor leader of the opposition party, said in a televised party meeting that the party will promptly start impeachment proceedings against Han who made it clear that he would not promulgate bills to appoint special counsels and investigate insurrection charges for the impeached president and scandals involving his wife.

The two bills were passed by the National Assembly on Dec. 12, and the Democratic Party had warned that if Han fails to promulgate the bills by Dec. 24, it would impeach the acting president.

Yoon, who was named by investigative units as a suspect on a treason charge, declared an emergency martial law on the night of Dec. 3, but it was revoked by the National Assembly hours later.

The impeachment motion against Yoon was passed by the National Assembly on Dec. 14 and delivered to the constitutional court to deliberate it for up to 180 days, during which Yoon's presidential power will be suspended.

Yoon has struggled with scandals involving his wife Kim Keon-hee during a presidential campaign and since he won the single five-year presidency in May 2022.

Kim was suspected of having been involved in stock price manipulation to gain illicit profits while having interfered in candidate nominations for the 2022 by-elections and the 2024 parliamentary elections and even in public opinion manipulation during the 2022 presidential election.