Hamas looked set to win about 30 percent of the vote in a Palestinian election on Wednesday with over 40 percent for President Mahmoud Abbas's Fatah, a senior source with one of the groups conducting exit polls said.
The poll was roughly in line with surveys ahead of the first parliamentary election in a decade.
Pollsters had cautioned that there would be a large margin of error in their projections, particularly because of the complicated Palestinian election system, under which some seats are chosen from party lists and some on a district basis.
Several institutes conducting exit polls have said they will not be published before 9.30 p.m. (1930 GMT).
A strong showing by Hamas in the election raised the possibility that the Islamic militant group, which is sworn to Israel's destruction, would join the Palestinian government for the first time.
Polling stations in the Gaza Strip and the occupied West Bank closed their doors at 7 p.m. (1700 GMT), but voters who were inside continued to cast ballots.