South Korea's main opposition party introduced a bill to impeach acting President Han Duck-soo on Thursday, a day before it plans to seek a vote on the move, which could deepen a constitutional crisis triggered by a short-lived martial law.

South Korea's main opposition party, the Democratic Party (DP), has filed a motion to impeach the country's acting President and acting leader, Han Duck-soo.

South Korea's opposition said Thursday it filed an impeachment motion against acting president Han Duck-soo, in an escalating row over the composition of the Constitutional Court which would decide whether to remove his predecessor from office.

Prime Minister Han Duck-soo, who became South Korea's acting president after Yoon Suk Yeol's impeachment, is a career technocrat whose wide-ranging experience and reputation for rationality may not be enough to stem the country's deepening political crisis.

South Korea’s main opposition party said Tuesday it will seek to impeach acting leader Han Duck-soo after he missed an opposition-set deadline to approve independent investigations into impeached Pres