The floor leader of South Korea's main opposition Democratic United Party stepped down Friday over his party's defeat in this week's presidential election, leaving the party leadership in a vacuum following the resignation of other senior party officials.

   Rep. Park Jie-won told a meeting of party lawmakers at the National Assembly that he is resigning to take responsibility for DUP presidential candidate Moon Jae-in's defeat in Wednesday's election.

   Park Geun-hye of the ruling Saenuri Party won the vote with just over 51 percent against Moon's 48 percent.

   "We did our best in every corner of the country to open a new era, but we lost," Park said. "We must follow a path of desperate self-examination and intense innovation."

   "Let's go forward with a determination to each carry our heavy responsibility," he said, adding that he offered his resignation to Moon on Thursday.

   DUP Chairman Lee Hae-chan stepped down last month along with other senior party members amid mounting calls for political reform. The string of resignations were seen at the time as a demonstration of the party's willingness to accept then independent presidential candidate Ahn Cheol-soo's demands for reform, which he had set as a condition for merging candidacies with Moon.

   The two liberal candidates later agreed to merge their candidacies in a bid to boost their chances against conservative front-runner Park, but Ahn dropped out of the race after negotiations with Moon on who should run as the single liberal contender fell through.

   The DUP is expected to soon form an interim leadership under a leader appointed by Moon, who has doubled as party chief since Lee's resignation.

(Yonhap News)