President Yoon Suk-yeol promises changes, top aides quit, after opposition parties sweep National Assembly elections.

With 99 percent of the votes counted, the main opposition Democratic Party (DP) and its satellite party appear to have won a combined 175 seats in the 300-seat parliament. The Rebuilding Korea party, considered allied with the DP, was expected to take about 12 seats, projections showed.

Yoon’s ruling People Power Party (PPP) and its satellite party were expected to have won 109 seats.

Turnout was 67 percent, the highest ever recorded for a parliamentary election. The National Elections Commission is expected to confirm the final results later on Thursday.

“When voters chose me, it was your judgement against the Yoon Suk-yeol administration and you are giving the Democratic Party the duty to take responsibility for the livelihood of the people and create a better society,” DP leader Lee Jae-myung said.

Lee defeated a conservative candidate considered a major Yoon ally to win his seat in the city of Incheon to the west of the capital, Seoul.

Wednesday’s election was widely seen as a mid-term confidence vote on Yoon, a former top prosecutor who narrowly beat Lee to take office in 2022 for a single five-year term.

Speaking after the scale of his party’s loss became clear, Yoon promised reform.

South Korea’s Yonhap news agency said Prime Minister Han Duck-soo and other senior aides all offered their resignations. The PPP leader Han Dong-hoon also quit.

Yoon has suffered low approval ratings for months amid a failure to deliver on his policy agenda and voter upset over rising prices and a series of corruption scandals.

The election setback is likely to further tie his hands domestically.

“Given his likely lame duck status, the temptation for Yoon will be to focus on foreign policy where he will still have statutory power,” said Mason Richey, a professor at Hankuk University of Foreign Studies.