Japan’s governing coalition has lost its upper house majority following elections that saw major gains for a right-wing populist party that warned of a “silent invasion” by foreigners.

Japanese Prime Minister Shigeru Ishiba’s coalition won 47 seats in the 248-seat House of Councillors in Sunday’s election, three short of the 50 it needed to retain control of the upper chamber.

The outcome left Ishiba’s Liberal Democratic Party (LDP) and junior partner Komeito with a combined 122 deputies in the upper chamber, which fills half of its seats in elections every three years.

The result marks another serious blow for Ishiba, whose government is locked in high-stakes trade negotiations with United States President Donald Trump’s administration, after his coalition lost control of the more powerful National Diet, the lower house, in elections in October.

Speaking late on Sunday as exit polls pointed to a drubbing for his coalition, Ishiba said he “solemnly” accepted the “harsh result”.

“It’s a difficult situation, and we have to take it very humbly and seriously,” Ishiba said in an interview with state broadcaster NHK.

Ishiba, who has led a minority government since losing control of the lower house, said he intended to stay on as prime minister despite the poor result.

Amid widespread discontent over rising living costs, the previously fringe Sanseito party broke into the political mainstream, picking up 14 seats on top of its one existing seat.

The party, which only holds three seats in the National Diet, capitalised on voter frustration over inflation and Japan’s moribund economy with warnings about immigration and populist pledges on tax cuts and social welfare.

Sanseito leader Sohei Kamiya, a 47-year-old former English teacher and supermarket manager, has stirred controversy with conspiracy theories about vaccines and “globalist elites”, and cited Trump’s “bold political style” as inspiration.

In an interview with Nippon Television after the vote, Kamiya defended his “Japanese First” slogan.

“The phrase was meant to express rebuilding Japanese people’s livelihoods by resisting globalism. I am not saying we should completely ban foreigners or that every foreigner should get out of Japan,” he said.

Despite denying accusations of xenophobia, Sanseito built its platform on nationalist appeals and fears of a “silent invasion” by immigrants.

Political analysts say the party’s message resonates with many Japanese voters facing a stagnant economy and a weakening yen, which have drawn record numbers of tourists and fuelled inflation.

Foreign residents in Japan reached a record 3.8 million last year, only about 3 percent of the population, but concerns about immigration remain present, even if not dominant.

NHK polling before the election showed that just 7 percent of respondents considered immigration as their main concern. Far more voters expressed anxiety over the country’s declining birthrate and rising food prices, particularly rice, which has doubled in cost over the past year.

“The buzz around Sanseito, especially here in the United States, stems from its populist and anti-foreign message. But it’s also a reflection of the LDP’s weakness,” said Joshua Walker, the president of the US-based Japan Society.

While Sanseito has drawn comparisons with far-right European groups such as Germany’s AfD and Reform UK, right-wing populism is a relatively new phenomenon in Japan, where such movements have historically struggled to gain traction.