The Japanese political world was rocked Sunday after media reports emerged that Prime Minister Shinzo Abe plans to dissolve the Lower House as early as Sept. 28 and call a snap election to take advantage of a disorganized opposition.

Major media outlets, including Kyodo News, Asahi Shimbun, NHK and Sankei Shimbun, all reported that Abe is considering dissolving the powerful Lower House soon and would call a general election next month, possibly on Oct. 22 or 29.

Abe is likely to decide on a specific date for the election after returning to Japan from a diplomatic tour to New York on Sept. 22, the reports said, quoting unnamed sources in the Liberal Democratic Party-Komeito ruling coalition.

The reports prompted three opposition parties — the Democratic Party, Social Democratic Party and Liberal Party — to cancel a planned meeting of their top leaders Sunday.

DP President Seiji Maehara had reportedly been considering forming a joint parliamentary group with the other two parties at the meeting, but it was abruptly canceled, with the DP now looking to prioritize preparations for a possible Lower House poll, a party source said.

Rumors had circulated in recent weeks among the political elite that Abe would dissolve the Lower House on Sept. 28, when an extraordinary session of the Diet is scheduled to start.

“All the Lower House members now have come to believe that the timing (of a general election) is not so distant,” LDP General Council chairman Wataru Takeshita said Saturday during a party meeting in the city of Tokushima.

The Abe Cabinet’s approval rating — a critical indicator for the arguably populist prime minister — have rebounded significantly in media polls after suffering a sharp plunge in the wake of scandals over alleged government favoritism involving school operators Kake Gakuen and Moritomo Gakuen in recent months.

Meanwhile, backing for the DP, the largest opposition force, has remained stagnant at a level far outpaced by that of Abe’s LDP.

A national party led by Tokyo Gov. Yuriko Koike, if formed, could be a powerful rival to the LDP, but lawmakers close to the popular leader are still in the early stages of preparations for any launch of a new political party.

These factors have combined to fuel speculation that Abe would soon dissolve the Lower House, which has the final say in choosing a prime minister after a general election.

Lower House members’ current terms end in December next year, and an election is required by law to be held by that time at the latest.

Abe is also no doubt anticipating the looming end to his current term as LDP president in September next year.

By holding an early election, Abe could benefit by extending his party’s grip on power into the waning, lame-duck days of his final term, political observers have said.

A key focus of the election is likely to be whether political coalitions wanting to revise the postwar Constitution, including Abe’s LDP and its junior partner, Komeito, will be able to retain more than two-thirds of the 465-seat chamber.

To initiate a national referendum to revise the pacifist Constitution, support of more than two-thirds of both the Lower and Upper Houses is required. Currently pro-revision forces occupy more than two-thirds of the both chambers, although they have yet to form a consensus on which article should be revised and how.

The Abe Cabinet’s approval rating in a monthly poll by NHK surged to 44 percent in the latest survey conducted from Sept. 8 through Sept. 10 after hitting a low of 35 percent in July.

Other media polls have likewise reported a rebound of the support rate for the Abe Cabinet, partly on the back of the prime minister’s handling of the North Korean nuclear and missile crisis.