JERUSALEM — Seizing the initiative in Israel’s postelection political gridlock, Prime Minister Benjamin Netanyahu on Thursday called on his main rival, Benny Gantz, to meet immediately to discuss forming a government of national unity together.

Mr. Netanyahu, facing a looming indictment in three corruption cases, is fighting for his political survival and, potentially, his freedom. His only chance of gaining immunity from prosecution would be to remain in the top office, though neither he nor Mr. Gantz emerged from Tuesday’s election with a clear path to the premiership.

[Update: Netanyahu is chosen to form Israel’s next government.]

Mr. Gantz had already called for a unity government, but for Mr. Netanyahu, time is of the essence. He has a special hearing with the attorney general set for Oct. 2, and charges could be filed soon after.

Tuesday’s redo election was Israel’s second in five months, after an April ballot also ended inconclusively.