Ken Bredemeier and Linda Gradstein contributed to this report.

Israeli political challenger Benny Gantz said Thursday that he, not Prime Minister Benjamin Netanyahu, should lead a new unity government after Gantz's centrist Blue and White party won the most seats in parliament in this week's election.

There was no clear winner in Tuesday's election, but Gantz's party won 33 seats to 31 for Netanyahu's right wing Likud party, both well short of a 61-seat majority in the 120-seat Knesset. Neither can immediately muster a majority with their smaller political allies.

Both Netanyahu, Israel's longest-serving leader, and Gantz, a former Israeli defense chief, called for a unity government, but Gantz said he should lead the next government since his party won more seats than Likud.

"The public voted clearly in favor of unity," Gantz said.

"Blue and White has at the time I am speaking won 33 seats, while Netanyahu has not obtained a sufficient majority to form a coalition as he hoped."

Gantz added, "We will listen to everyone, but we will not accept mandates imposed on us."

Israeli President Reuven Rivlin said he will begin consultations Sunday with the multiple parties elected to parliament to decide who should be given the chance to form a new government. The talks could last a couple days.

Rivlin praised Netanyahu's call for a unity government, but the Israeli leader, who faces possible corruption charges in the coming weeks, has shown no indication he is willing to give up the premiership. He was seeking a record fifth term as the Israeli leader.

"Throughout the campaign I called for a right-wing government, but unfortunately the election results show that's not possible," Netanyahu said in a video statement. "Therefore there is no choice but to form a broad unity government."

He said there was "no reason" to call a third election, following the inconclusive vote in April and Tuesday's balloting.

The close vote between Gantz and Netanyahu could make Avigdor Lieberman of the secular nationalist Yisrael Beitenu (Israel Our Home) party the key player in deciding who becomes prime minister. It won eight seats in the new parliament.

But Lieberman is refusing to sit with Netanyahu's ultra-Orthodox religious allies, instead calling for a broad, secular unity government with Likud and Blue and White.

Meanwhile, Blue and White also has vowed not to join with Likud if Netanyahu remains as part of the government because he is facing possible corruption charges in the coming months.

Lieberman, speaking outside his home in the Jewish settlement of Nokdim, said, "A national unity government, a broad liberal government. We will not join any other option. From our point of view, no other option exists."

He laid out a series of demands, including civil marriage in Israel. Currently, the ultra-Orthodox Rabbinic authorities have sole control of marriage and divorce in Israel. He also insisted that all ultra-Orthodox students study a secular curriculum of math and science, and that public transportation operate on the Jewish Sabbath.

After the last election in April, Netanyahu was just one seat short of a 61-seat majority. But Lieberman refused to join his government, which was set to include the ultra-Orthodox, unless the government passed a law to draft ultra-Orthodox yeshiva students into the military - a controversial issue that has led to violent ultra-Orthodox demonstrations.

This time, a national unity government seems more likely.

Analyst Yossi Klein Halevi of the Hartman Institute said, "Almost certainly this, what we can call a broad mainstream unity government will exclude the hard ideological camps on the right and the left. That's the only way you can have these two parties sitting together is if their satellite parties are excluded, because the satellite parties are perceived by each party to be too extreme. And so, the coalition again will have to pull more toward the center."

Netanyahu is facing a series of corruption charges, and police have recommended he be indicted on three of them. He is supposed to have a final hearing before indictment in the next month.

Forming a new government could take several weeks.

Yohanan Plesner, president of the Israel Democracy Institute, said, "We might enter a period of days and perhaps weeks, when it is unclear who is going to be the prime minister. This is an unprecedented situation, because neither Mr. Netanyahu has a majority of 61 nor does Mr. Gantz. So, we are about to enter a period of political uncertainty."

Palestinian Foreign Minister Riyad al-Maliki said Wednesday he is prepared to restart peace talks with whomever is able to form a new Israeli government. But he did not say if that includes Netanyahu, under whose leadership peace with the Palestinians has been elusive.