Benny Gantz, leader of the center-left Blue and White party (Kahol Lavan), on Thursday rejected Israeli Prime Minister Benjamin Netanyahu's offer to form a government.
In the first party meeting since Tuesday's parliamentary elections, Gantz said he is now the leader of the largest party in Israel.
"I want to establish a broad and liberal unity government headed by me to bring about the will of the people of Israel," he said
Responding to Netanyahu's call for a unity government, he said: "You don't approach establishing a unity government with blocs and spins."
Netanyahu said it is impossible to form a unity government without a meeting between the two major party leaders.
"I was disappointed that at this time Benny Gantz still refuses to meet," Netanyahu said.
Earlier on Thursday, Netanyahu called Gantz to form a unity government, according to Israeli local media reports.
The move came after it became clear that the right-wing parties have no majority to form the next Israeli government.
On Wednesday, he met with the leaders of religious right-wing parties Yamina, Shas, and United Torah Judaism to negotiate as one bloc.
The Israeli election committee is expected to announce the final results Thursday evening.
With 90% of the votes counted, Israel's center-left Blue and White Party is projected to win the parliamentary elections with 32 seats, edging ahead of Netanyahu's Likud party at 31 seats.
#IsraElex19: Israeli Elections 2019
The Arab bloc (Israeli Arabs) was able to win 13 seats.
The right-wing Yisrael Beiteinu party of former Defense Minister Avigdor Lieberman bagged nine seats.
Voter turnout stood at 63.1%, according to the election committee.
Israel held its second general elections this year, due to Netanyahu's failure to form a government after the previous poll. Observers expect there may be a third round of elections if the crisis continues.