TOKYO >> Japan’s leader has scored a major victory in national elections that returned his ruling coalition to power in decisive fashion.

Japanese media said Monday that Prime Minister Shinzo Abe’s Liberal Democratic Party and a small coalition partner had together secured at least 312 seats in the 465-seat lower house of parliament, passing the 310-barrier for a two-thirds majority. Four seats remained undecided.

The victory boosts Abe’s chances of winning another three-year term next September as leader of the Liberal Democratic Party. That could extend his premiership to 2021, giving him more time to try to win a reluctant public over to his longtime goal of revising Japan’s pacifist constitution.

In the immediate term, the win likely means a continuation of the policies Abe has pursued since he took office in December 2012 — a hard line on North Korea, close ties with Washington, including defense, as well as a super-loose monetary policy and push for nuclear energy. Stocks rose in Tokyo on Monday morning.

Abe’s ruling coalition already has a two-thirds majority in the less powerful upper house. Having a so-called supermajority in both houses gives them virtually a free hand to push even divisive policies and legislation.

Abe said the results indicate that voters support his policies and want to see his political leadership continue.

“I think the results reflected the voters’ preference for a solid political foundation and their expectations for us to push polices forward and achieve results,” Abe told NHK.

With the win, Abe has bounced back from the summer, when his support ratings plunged to 30 percent after accusations of government favoritism to people connected to him. For the first time since he took office nearly five years ago, he appeared vulnerable as both party leader and prime minister.

The ruling coalition’s victory, though, reflects as much the lack of viable alternatives as support for Abe, a fact that he seemed to acknowledge in post-election comments. Turnout was just 54 percent, as typhoon rains lashed much of the country.

“I will humbly face the victory and continue to work humbly and sincerely,” he told NHK, noting lingering public distrust over the scandals.

Abe dissolved the lower house less than a month ago, forcing the snap election. Analysts saw it as an attempt to solidify his political standing at a time when the opposition was in disarray and his support ratings had improved somewhat.

His plan was briefly upstaged by the launch of a new opposition party by populist Tokyo Gov. Yuriko Koike. But initial excitement faded, and the Party of Hope took only 49 seats.

Another new party, the Constitutional Democratic Party of Japan, won 54 seats and looks to be the biggest opposition grouping. It is liberal-leaning, while both the Party of Hope and Abe’s Liberal Democratic Party are more conservative.

Koike called the results “very severe” in a televised interview from Paris, where she is attending a conference of mayors. She said some of her remarks might have been taken negatively by voters, and that she would take the blame.

Abe’s party and its nationalist supporters have advocated constitutional revisions for years. They view the 1947 constitution as the legacy of Japan’s defeat in World War II and an imposition of the victor’s world order and values. The charter renounces the use of force in international conflicts and limits Japan’s troops to self-defense, although Japan has a well-equipped modern military that works closely with the U.S.

Any change to Japan’s constitution, which has never been amended, requires approval first by two-thirds of parliament, and then in a public referendum. Polls indicate that the Japanese public remains opposed to amendment.