With 98 percent of the vote counted in Israel's election, Kahol Lavan grew by one seat to 33, widening its edge over Prime Minister Benjamin Netanyahu's Likud Party.
Kingmaker Avigdor Lieberman's Yisrael Beiteinu party lost a seat, leaving it with eight in the incoming Knesset.
The results give the center-left a slight advantage of 57 seats, compared to 55 seats for the right-wing bloc.
Likud has 31 seats, two less than Kahol Lavan.
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The Joint List, made up of four Arab-majority parties, is the third largest party with 13 seats, the same number they received in their maiden joint run in 2015.
The ultra-Orthodox parties, Shas and United Torah Judaism, received nine and eight seats respectively. Ayelet Shaked's Yamina got seven seats. Labor-Gesher currently have six seats, while the Democratic Union has five.
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As neither the right nor left have a clear majority to form a governing coalition, Netanyahu called on Benny Gantz to meet with him Thursday and form a broad unity government.