TOKYO (AP) — Japan’s Prime Minister Shigeru Ishiba announced Sunday that he will resign, following growing calls from within his party to take responsibility for a historic defeat in July’s parliamentary election.

Ishiba, who took office in October, said he was stepping down as prime minister and as the head of his conservative Liberal Democratic Party.

Ishiba, a 68-year-old centrist, had resisted demands from opponents further to the right within his own party to resign. He argued that he wanted to avoid a political vacuum at a time when Japan faces key domestic and international challenges, including U.S. tariffs, rising prices and growing tensions in the Asia-Pacific.

Ishiba explained at a news conference Sunday night that he had intended for some time to take responsibility for his party’s summer election loss, but was first determined to make progress in tariff negotiations with the United States. He described it as matter of the national interest.

“Who would seriously negotiate with a government whose leader says he is stepping down?” Ishiba said.

He said the moment had arrived with an order by U.S. President Donald Trump on Friday to lower tariffs on Japanese cars and other products from 25% to 15%.

“Having reached a milestone in the U.S. tariff negotiations, I decided now is the time to make way for a successor,” Ishiba said.

The resignation came one day before Ishiba’s party was to decide whether to hold an early leadership election, which would have amounted to a virtual no-confidence motion against him if approved.

He said he made the “painful decision to resign” to avert that step because “it would cause a critical division within the party, and that is absolutely not my intention.”

Ishiba said he would instead start a process to hold a party leadership vote to choose his replacement, which is expected to be held in October. He is to remain as prime minister until a new leader is elected and endorsed by the parliament.

Ishiba’s leadership that lasted only one year underscores the instability of Japan’s minority government.

A maverick who won the leadership in his fifth attempts, Ishiba said he regrets he could not live up to voters’ expectations for change. “As a result, I failed to go my own way, and I wonder how I could have done better,” he said.

He said he is not going to run in the next leadership race, even though he regrets leaving behind unfinished business, such as measures for salary increases, agricultural reforms and further strengthening Japan’s security. He asked his future successor to tackle the issues he cherished.

In July, Ishiba’s ruling coalition failed to secure a majority in the 248-seat upper house in a crucial parliamentary election, weakening his government. The loss followed a defeat in the more powerful lower house, where the party-led coalition lost its majority in October, only two weeks after Ishiba took over.

Liberal Democratic lawmakers who support the prime minister said those who lost seats were largely ultra-conservatives who were linked to corruption scandals before Ishiba took office. Public polling showed that pressure on Ishiba to resign had the reverse effect and caused his support to grow.

Calls for Ishiba to step down grew after the Liberal Democratic Party last week called for a “complete overhaul” of the party following its losses.

Taro Aso, a conservative heavyweight known for his anti-Ishiba stance, and a minister and several deputy ministers in the Ishiba Cabinet requested an early vote, prompting others to follow suit.

Former Health Minister Norihisa Tamura said on a talk show of the public broadcaster NHK earlier Sunday that the best way to heal party divisions and move forward is for Ishiba “to settle” the dispute before Monday’s vote. The party has already been distracted from necessary work on economic measures and on figuring out ways to gain opposition support in the next parliamentary session, Tamura said.

Possible candidates to replace Ishiba include Agriculture Minister Shinjiro Koizumi, as well as ultra-conservative former economic security minister Sanae Takaichi and Chief Cabinet Secretary Yoshimasa Hayashi, a moderate and the protege of former Prime Minister Fumio Kishida.

Lacking a majority in both houses, the next party leader will have to work with the main opposition parties to get bills passed, experts say, or else face constant risks of no-confidence motions.

The opposition parties, however, are too splintered to form a coalition to topple the government.

Voters say they want to see the party move forward and get down to work but they worry about uncertainty.

Office worker Takahiro Uchi welcomed Ishiba’s resignation, as he hopes for change, “but at the same time, there is also uncertainty and concern about who will take over next.” Masataka Nishioka, who works for a dental equipment company, said, “I really hope for a kind of politics that makes life easier for everyone.”

TOKYO (AP) — Japan said Tuesday it plans to use some slightly radioactive soil stored near the tsunami-wrecked Fukushima nuclear plant on flower beds outside Prime Minister Shigeru Ishiba’s office to show it is safe to reuse.

The soil was removed from across the Fukushima prefecture as part of decontamination work following the 2011 nuclear disaster and has since been in interim storage. Some of it has since reached levels safe enough for reuse, officials say.

Using the soil at Ishiba’s office in Tokyo is aimed at reassuring the public it is safe. The government said that it plans to reuse the soil for flower beds and other purposes within the grounds of government agencies. The plan is based on guidelines set by the Environment Ministry in March and endorsed by the International Atomic Energy Agency.

The Fukushima disaster resulted in large amounts of radioactive materials spewing out from the plant, polluting surrounding areas.

Japan is stuck with large volumes of the dirt, chopped trees and other debris collected during intensive decontamination work. It has 14 million cubic meters of dirt and other materials — enough to fill 11 baseball stadiums — stored at a sprawling outdoor facility straddling the towns of Futaba and Okuma, near the Fukushima plant.

The government is aiming to find disposal sites for the soil by 2045, with officials suggesting low risk material could be used to build roads and in other public works projects across the country.

The Environment Ministry said that the soil will be used as foundation material and safely covered with top soil thick enough to keep radiation at negligible levels.

But there is much public unease. The government has already been forced to discontinue a plan to experiment using some of the soil in flower beds at several public parks in and around Tokyo following protests.

The IAEA is providing assistance with the Fukushima decommissioning process, which requires removing more than 880 tons of melted fuel debris.

In 2023 Japan began discharging treated radioactive wastewater from the plant into the sea to reduce the risk of accidental leaks and to make space to build facilities needed for melted fuel removal.