SEOUL - South Korea's main liberal opposition Democratic Party will submit a motion on Tuesday to impeach Prime Minister Han Duck-soo, who became the acting president following the impeachment of President Yoon Suk-yeol, according to multiple media outlets.

The party's floor spokesman told reporters right after the general meeting of its lawmakers that the party unanimously decided to table the motion later in the day and report it to the National Assembly's plenary session on Thursday.

Park Chan-dae, floor leader of the Democratic Party, said earlier in the day that his party would immediately launch impeachment proceedings against Han who made it clear that he will not promulgate bills to appoint independent counsels and investigate insurrection charge for the impeached president and scandals involving his wife.

The two bills were passed through 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 him.

Yoon, who was named by investigative units as a suspect on treason charge, declared an emergency martial law on the night of Dec 3, but it was revoked by the National Assembly hours later.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 in the National Assembly on Dec 14 and was delivered to the constitutional court to deliberate it for up to 180 days, during which Yoon's presidential power was 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.