SEOUL—South Korea’s legislature voted to impeach acting President Han Duck-soo on Friday after he declined to make judicial appointments needed to advance the impeachment of his predecessor, extending the political upheaval that began with a short-lived martial law declaration earlier this month.

The vote intensifies a political crisis as the Constitutional Court meets for its first hearing on suspended President Yoon Suk Yeol's short-lived martial law.

The assembly approved the impeachment motion in a 192-0 vote on Friday. Governing party lawmakers boycotted the vote.