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.

South Korean investigators have left the president’s official residence after a nearly six-hour standoff during which he defied their attempt to detain him.

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