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 has submitted a motion to impeach the country’s acting leader over his reluctance to fill three Constitutional Court vacancies ahead of the court’s review of rebell

South Korean investigators have issued a new summons to suspended President Yoon Suk Yeol for questioning about the failed martial law decree earlier this month, Seoul-based Yonhap News reported.

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 opposition party filed a motion to impeach Acting President Han Duck-soo after he resisted pressure to appoint court judges who might increase the likelihood of removing President Yoon Suk Yeol from power.

South Korean President Yoon Suk Yeol failed to appear before law enforcement authorities for questioning on Wednesday - the second time he has ignored a summons over his attempt to impose martial law.

South Korea’s President Yoon Suk Yeol again declined to appear for questioning by investigators over his martial law declaration as the embattled leader seeks to first defend himself at an impeachment trial.