Israel's president, Isaac Herzog, has picked Gadi Eisenkot, the strongest challenger to Prime Minister Benjamin Netanyahu, to make the first attempt at forming a new government after an inconclusive vote.

Herzog's office said on Saturday night that it had told Eisenkot, who leads the Yashar party, of the decision. The formal mandate is due to be handed over at a ceremony at the presidential residence in Jerusalem on Sunday. Eisenkot will then have 28 days to assemble a coalition, with the option of an extension of up to two more weeks. If he cannot do so, Netanyahu is widely expected to be given his own turn.

The election on 27 October cost Netanyahu's religious nationalist alliance its majority, yet his camp remains the biggest bloc in the 120 seat Knesset with 53 seats. Eisenkot's broad opposition grouping holds 48. Neither side can reach the 61 seats needed to govern alone.

During consultations with the president, Eisenkot won the backing of both Arab majority lists, which made record gains in the vote and could now decide the outcome. It is still uncertain whether his allies would accept their support in a coalition.

Eisenkot, 66, served as military chief of staff between 2015 and 2019. He has promised to heal divisions after years in which the country swung sharply to the right, and has pledged to confront violent settlers in the West Bank, calling recent attacks on Palestinians a form of Jewish terror tolerated by the outgoing government.

He is far from a dove, however. He rejects a Palestinian state, has vowed to end Hamas rule in Gaza and to dismantle its armed wing, and is associated with a doctrine of overwhelming force against civilian infrastructure in areas held by Hezbollah, developed during the 2006 war in Lebanon.

If he succeeds, he would end the tenure of Israel's longest serving prime minister.