SEOUL -- South Korea's opposition-controlled parliament voted Friday to impeach Prime Minister Han Duck-soo who had been serving as acting president following President Yoon Suk-yeol's impeachment.

National Assembly Speaker Woo Won-shik said in a televised plenary session that the motion to impeach Han was passed with 192 votes in favor in the 300-member unicameral parliament.

It was the first time in the country's modern history that an impeachment motion against an acting president is put to a vote and passed in the National Assembly.

Before leaving the parliamentary chamber to boycott the vote, 108 lawmakers of the ruling People Power Party chanted in union in front of the parliamentary speaker, "Null and void," and "Resign, speaker."

The ruling and opposition parties had been divided over the requirement for the acting president's impeachment.

The People Power Party claimed that 200 lawmakers should vote for the impeachment as it applies to the president's impeachment, but the opposition parties said a majority of 151 votes are needed as Han is a member of the cabinet.

With the parliamentary approval, Han's duty will be suspended until the constitutional court completes deliberation on it.

Minister of Economy and Finance Choi Sang-mok, who doubles as deputy prime minister for economic affairs, will assume an acting presidency.

Han's impeachment came after he officially refused to approve the appointment of three constitutional court justices who will fill vacancies on the nine-member bench for Yoon's impeachment trial.

The impeachment motion against Yoon was passed in the National Assembly on Dec. 14 and was delivered to the constitutional court to deliberate it for up to 180 days, during which Yoon's presidential power is suspended.

Yoon, who was named by investigative agencies as a suspect on insurrection charge, declared an emergency martial law on the night of Dec. 3, but it was revoked by the National Assembly hours later.

To oust Yoon from office, at least six out of nine constitutional court justices are required to uphold the impeachment motion.