Han Dong-hoon, former interim leader of the ruling People Power Party, announces his bid for party leader during a press conference at the National Assembly in Seoul, Sunday. Yonhap

Han Dong-hoon, the former interim leader of the ruling People Power Party (PPP), who has maintained a low profile since the party's defeat in the April 10 parliamentary elections, announced his bid for party leadership Sunday, pledging to seek to reestablish a horizontal party-government relationship.

The PPP plans to hold a national convention on July 23 to elect a new leader.

Han emphasized his intention to establish a more equal relationship between the party and the government. He noted that, up to now, the party has been unable to voice even reasonable criticisms of the government's policy or political decisions.

"I will reestablish party-government relations in a horizontal way," Han said. "The party should faithfully cooperate with the government, but I will not mind providing reasonable checks, criticisms and suggestions for change when necessary."

He also promised to regain the conservative party's public reputation and reform the party.

"I will rebuild the party that understands the needs and expectations of the public, supporters and members. I will seek closer cooperation between the party and the government," Han said during a press conference at the National Assembly in Seoul.

"I will use the experience of (an election) defeat for the foundation for change and victory."

Han, a former prosecutor and President Yoon Suk Yeol's first justice minister, became the conservative party's interim leader in December and led the tough election campaign to help the party regain voters' trust. Despite such efforts, the party won only 108 seats out of the 300-member National Assembly, and Han stepped down shouldering responsibility for the defeat.

Rep. Na Kyung-won announces her candidacy for party leader during a press conference at the National Assembly in Seoul, Sunday. Yonhap

On the same day, Rep. Na Kyung-won and former Land Minister Won Hee-ryong, who lost to Democratic Party of Korea (DPK) Chairman Lee Jae-myung in the parliamentary elections, also announced their candidacy for party leader.

Na emphasized her experience as a five-term lawmaker, while Won stressed his ability to communicate smoothly with the presidential office.

Branding herself as the right person to reform the party, Na said, "As a lawmaker, I have managed to stay out of factional conflicts within the party. I will pour out all my wisdom, strategy and experience to bring conservatives back to power. There is no time for trial and error. I can turn the Yoon administration into success. We will overcome difficulties and find solutions to problems. We will go together."

Won said he can guide the party to victory as "one team."

"The party-government relationship can be established only if there is trust. I have trust in President Yoon and vice versa," he said. "I will convey the sentiments of the party and the public to the president without hesitation and share the result with citizens. I will cooperate but not kneel down."

Former Land Minister Won Hee-ryong announces his bid for party leader during a press conference at the National Assembly in Seoul, Sunday. Yonhap

Rep. Yoon Sang-hyun, another five-term lawmaker, announced his bid Friday, making the election a four-way race. Yoon has appealed to traditional conservative supporters, saying, "The party leader should be someone who has fought and won against the DPK and has a deep trust with the president and can speak up about various issues."

Han had clashed with Yoon over politically sensitive issues in the run-up to the elections, including how to handle allegations surrounding first lady Kim Keon Hee that she received a luxury bag as a gift in 2022.

Han has been garnering unabated support from conservative supporters. In a Gallup Korea poll of 1,008 adults on June 14 and 15, which surveyed the popularity of potential candidates for the PPP's new chairperson, Han received 59 percent support, followed by Na at 10 percent.

Rep. Ahn Cheol-soo and former PPP lawmaker Yoo Seong-min, who were viewed as potential competitors, have ruled themselves out of the post. Ahn said he would not run for the party leadership, adding he would focus on more urgent tasks.

"I will not run for party leader. I have concluded that it is a meaningless challenge," Yoo wrote on Facebook, Friday.

The hopefuls were divided over a special counsel probe into allegations that the Yoon administration influenced the military's investigation into the death of a Marine last year. The DPK has been pushing the bill unilaterally despite a boycott from the PPP and a presidential veto.

Han said the PPP should push for the bill to clear doubts on the government's alleged interference in the military's probe.

Na and Won said they may discuss the bill once the ongoing investigations by the Corruption Investigation Office for High-ranking Officials are finalized.

The bill sought to launch an independent counsel investigation into the government's alleged interference in the military's investigation of the death of Marine Cpl. Chae Su-geun during a flood rescue operation in July 2023. The DPK and minor opposition parties suspect that the allegations may involve high-ranking government officials, potentially including the president himself.