Jerusalem - Prime Minister Benjamin Netanyahu called on Thursday on his main rival, former general Benny Gantz, to join him in a broad, governing coalition after Israel's election ended with no clear winner.
A spokeswoman for Gantz, leader of the centrist Blue and White party, had no immediate response to the surprise offer from Netanyahu, head of the right-wing Likud party.
The change of strategy reflected Netanyahu's weakened position after he failed again in Tuesday's election, which followed an inconclusive ballot in April, to secure a parliamentary majority.
"During the election campaign, I called for the establishment of a right-wing government but to my regret, the election results show that this is impossible," Netanyahu said.
"Benny, we must set up a broad unity government, as soon as today. The nation expects us, both of us, to demonstrate responsibility and that we pursue cooperation."
On Wednesday, Gantz said he hoped for a "good, desirable unity government". But he has also ruled out forming one with a Netanyahu-led Likud, citing looming corruption charges against the prime minister. Netanyahu denies any wrongdoing
Prospect of third poll days after vote
Israelis were contending with the prospect of a third election on Thursday, two days after an unprecedented repeat election left the country's two main political parties deadlocked, with neither Prime Minister Benjamin Netanyahu nor his rivals holding a clear path to a coalition government.
While weeks of negotiations to form a coalition government lay ahead, conditions set by the parties could hobble the task within the allotted time, prompting a never-before held third election.
With nearly all votes counted Thursday, the centrist Blue and White party stood at 33 seats in Israel's 120-seat parliament. Netanyahu's conservative Likud stood at 31 seats.
"Everyone will need to get off their high horse to prevent elections for the third time," Likud lawmaker David Bitan told Israeli Army Radio. "Blue and White's desire for a unity government under their terms will not work."
The candidate has 42 days to do so and, if he fails, the president can give another candidate 28 days to form a coalition. If that fails, the president can assign another parliament member the task of building a government, or he can call new elections, something that has never happened. Rivlin has promised he will do everything in his power to prevent a third election.
The deadlock follows the second Israeli elections this year, which were called because Netanyahu failed to cobble together a coalition following the April vote.
Israelis endured a caustic campaign that saw a combative Netanyahu fighting for his political survival amid the recommendation by Israel's attorney general to indict him on charges of bribery, breach of trust and fraud pending a hearing in early October.
Netanyahu had sought an outright majority with his allies in hopes of passing legislation to give him immunity from the expected indictment, which would otherwise increase the pressure on Netanyahu to step aside.
The vote was largely seen as a referendum on Netanyahu, who this summer surpassed Israel's founding prime minister to become the country's longest-serving leader. During the campaign Netanyahu cast himself as a seasoned statesman who was the only candidate able to steer Israel through a sea of challenges.
His challenger, Blue and White's Benny Gantz, a former army chief, tried to paint Netanyahu as divisive and scandal-plagued, offering himself as a calming influence and honest alternative.
Despite the scorched earth campaign that saw Netanyahu thrash institutions like the media, the police and the electoral committee - and which was tinged with anti-Arab rhetoric - the longtime leader failed to secure the resounding victory he needed to guarantee his political survival and perhaps save himself from a formal indictment.