Tokyo. Japanese Prime Minister Shigeru Ishiba said he will make a decision on resigning over a historic defeat of his ruling party in a weekend election after closely studying the tariff deal just struck with the United States.

Ishiba has been under growing pressure to step down as his ruling Liberal Democratic Party and its junior coalition partner, Komeito, lost their majority in the 248-member upper house, the smaller and less powerful of Japan's two-chamber parliament on Sunday, shaking his grip on power and Japan's political stability.

The loss means Ishiba's ruling coalition, which also lost a majority in the more powerful lower house in October, now lacks a majority in both houses of parliament, making it even more difficult for his government to achieve any policy goals and worsening Japan's political instability.

Ishiba had announced his intention Monday to stay on to tackle pressing challenges, including tariff talks with the United States, without creating a political vacuum, sparking calls from inside and outside his own party for a quick resignation to respond to the election results.

With the tariff deal with the US paving the way for his possible departure, Japanese media said he is expected to soon announce plans to step down in August.

Ishiba welcomed the trade agreement Wednesday, which places a 15 percent tax on Japanese cars and other goods imported into the US from Japan, down from the initial 25 percent, saying it was a product of tough negotiations to protect the national interest and that it would help benefit both sides as they work together to create more jobs and investment.

But Ishiba declined to comment on his possible move and only told reporters that he has to closely examine the trade deal first.

In Sunday's election, voters frustrated with price increases exceeding the pace of wage hikes, especially younger people who have long felt ignored by the ruling government's focus on senior voters, rapidly turned to emerging conservative and rightwing populist parties, like the Democratic Party for the People and Sanseito.

None of the opposition parties have shown interest in forming a full-fledged alliance with the governing coalition but they have said they are open to cooperating on policy.

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