Unofficial results in Israel's second election in five months suggest it is too close to call, Israeli media say.
Incumbent PM Benjamin Netanyahu's party and that of his main challenger, Benny Gantz, are neck and neck with 32 seats each, the Kan public broadcaster says.
A prime minister needs to command a 61-seat majority in parliament. The smaller Yisrael Beiteinu party appears to hold the balance of power.
Official partial results are expected on Wednesday morning.
Benjamin Netanyahu, Israel's longest-serving prime minister, has been in office for 10 years and is vying to win a record fifth term in office.
The 69-year-old, who leads the right-wing Likud party, has pledged to annex Jewish settlements and a swathe of other territory in the occupied West Bank if he is returned to power.