TOKYO, Sept. 7 (Xinhua) -- Japanese Prime Minister Shigeru Ishiba on Sunday announced that he will step down as the head of the Liberal Democratic Party (LDP), amid growing calls for him to take responsibility for the party's election setback.

He also said he would not stand as a candidate in the upcoming LDP leadership election triggered by his resignation.

"I have made the painful decision to step down despite still having unfinished tasks," Ishiba told a press conference at the prime minister's office.

Expressing regret to the public, Ishiba said that the LDP must undergo genuine renewal, warning against "falling into easy populism" and stressing the need for the party to remain a tolerant and inclusive force.

Regarding trade, Ishiba said he had long considered talks on U.S. tariff measures as a responsibility of his administration.

With the signing of a memorandum of understanding last week, Ishiba said the negotiations have reached a milestone, which made him decide to make way for his successor.

In postwar Japan, the president of the LDP, the dominant political force since its founding in 1955, almost always becomes the country's prime minister, since the party commands the largest bloc of seats in the Diet.

When an LDP president resigns or is replaced, the prime ministership typically changes hands as well.

In a landmark political setback in July, Japan's ruling coalition lost its majority in the House of Councillors, signaling deep public dissatisfaction with the government.

The defeat follows a similar outcome in the 2024 House of Representatives election, leaving the ruling bloc a minority in both chambers of the parliament, a historic first since the LDP's founding in 1955.