South Korea's acting President Choi Sang-mok vowed to continue trilateral cooperation with Japan and the United States, saying on Friday his country's diplomacy remains steadfast despite an unprecedented political crisis at home.

The plane crash is the first major test for South Korea’s acting president, Choi Sang-mok, who was appointed the interim leader only on Friday, as the country grapples with a political crisis at the highest levels.

Han Duck-soo declined to make judicial appointments needed to advance the impeachment of his predecessor.

South Korean Acting President Choi Sang-mok called for national harmony and unity and for trust in the government in a New Year's address on Tuesday, amid an unprecedented political crisis sparked by impeached President Yoon Suk Yeol's short-lived martial law declaration.

South Korea's opposition-controlled National Assembly voted Friday to impeach acting President Han Duck-soo despite vehement protests by governing party lawmakers, further deepening the country's political crisis set off by President Yoon Suk Yeol's stunning imposition of martial law and ensuing impeachment.

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 President Yoon Suk Yeol and his wife.

South Korea's acting President Choi Sang-mok said on Tuesday he would immediately move to fill vacancies on the Constitutional Court in a effort to restore stability after the impeachment of two of his predecessors this month triggered political turmoil.

South Korean investigators failed to detain impeached President Yoon Suk Yeol after an hours-long standoff with his security forces.

STORY: South Korea's acting President Choi Sang-mok held an emergency meeting in Seoul on Sunday to discuss the country’s deadliest air disaster, just two days into his new job.:: Muan, South Korea “As the acting 'head of the government' responsible for the safety and lives of our residents,

South Korean authorities moved Friday to execute an unprecedented arrest warrant for President Yoon Suk Yeol over his botched attempt to declare martial law last month.