Prime Minister Benjamin Netanyahu and his chief challenger Benny Gantz are making their final appeals to voters ahead of crucial parliamentary elections that will determine whether the longtime Israeli leader stays in power.

Netanyahu has been buoyed by a tight alliance with President Donald Trump but clouded by a series of looming corruption indictments. He is seeking a fifth term in office that would make him Israel's longest-ever serving leader.

He faces his stiffest challenge in a decade from Gantz, a telegenic former military chief whose Blue and White party has inched ahead of Netanyahu's ruling Likud party in the polls.

Netanyahu, however, still appears to have the better chance of forming a coalition, with a smattering of small nationalist and ultra-Orthodox parties vowing to back him.