Japan's Prime Minister Fumio Kishida will not seek re-election as leader of the ruling Liberal Democratic Party (LDP), which he says needs a "new start".

The 67-year-old LDP veteran is expected to step down as PM after the party elects a new leader in September.

Support for Mr Kishida, who has been PM since 2021, has fallen in the wake of a corruption scandal involving his party, rising living costs and a slumping yen.

His approval ratings had plummeted to 15.5% last month - the lowest for a PM in more than a decade.

"In the upcoming presidential election, it's necessary to show the people that the Liberal Democratic Party will change," Mr Kishida said at a press conference on Wednesday announcing his decision.

"A transparent and open election, and free and open debate are important. The first easy-to-understand step that indicates that the LDP will change is for me to step back," he said.

Within the party, some have doubted whether Mr Kishida can lead the LDP to a win in the next general election due in 2025. The party has been in power almost continuously since 1955.

Still, LDP leaders were shocked by Mr Kishida's announcement.

A senior leader told broadcaster NHK that he had tried to persuade Mr Kishida to run for office, but the prime minister said that would have been "irresponsible".

A member of Mr Kishida's faction in the party called the decision "very regrettable and unfortunate", adding that tehe PM "had a good record in foreign policy, defence policy, and domestic politics, but he was forced to [step down] due to the issue of politics and money."

Analysts have told the BBC that Japan is going through a "once-in-a-generation" political crisis as the ruling party fights to clean up its image.

Last December, four LDP cabinet ministers resigned within a fortnight over a fundraising scandal involving the ruling party's most powerful faction.

Five senior vice-ministers and a parliamentary vice-minister from the same faction, formerly led by the late PM Shinzo Abe, also quit.

Japan’s prosecutors launched a criminal investigation into whether dozens of LDP lawmakers received proceeds from fundraising events that saw millions of dollars kept off official party records.

But Mr Kishida's handling of the fundraising scandal drew public criticism, which made him more unpopular.

The controversy also unfolded as Japanese households struggled with food prices soaring at the fastest rate in almost half a century.

The combination of economic woes and political scandal fuelled mistrust in the ruling party, despite a weak and divided opposition.

"From now on, the entire political situation will be in flux," Jun Azumi, an MP from the main opposition Constitutional Democratic Party told NHK, after Mr Kishida's announcement.

Mr Kishida comes from a family of politicians - both his father and grandfather were members of Japan's House of Representatives.

He was first elected to the House in 1993. He went on to become Japan's longest-serving foreign minister when he held the post between 2012 and 2017.

He took over as PM in October 2021, succeeding Yoshihide Suga who resigned after just one year in office. He led the LDP to victory shortly after in the 2021 general election.

In the last three years, Mr Kishida's government pushed for policies to lift wages and household incomes amid a cost-of-living crunch.

He oversaw Japan's reopening after the Covid-19 pandemic, and was in office when the country experienced one of its most shocking political moments - the assassination of former PM Shinzo Abe in July 2022. He also made the controversial decision to honor the slain leader with a state funeral.

Even though he struggled domestically, Mr Kishida regularly made headlines for his diplomacy.

Japan has long been a key US ally in a fraught Indo-Pacific where it faces an assertive China and a nuclear-armed North Korea. And Mr Kishida has been successful in expanding the country’s military budget and taking cautious steps away from its post-war pacifist ideals.

Defence cooperation with Washington has deepened under his government, and he also mended relations with South Korea, receiving President Yoon Suk Yeol in Tokyo on a historic visit.

In another unprecedented move, Japan, the US and South Korea issued a joint statement at a Camp David summit last August, calling for expanding cooperation among them.

Additional reporting by Chika Nakayama in Tokyo