According to Palestinian sources, four men were killed in an Israeli anti-terrorist operation in the occupied West Bank.
The Israeli border police announced on Monday that security forces broke into a refugee camp in Jenin to arrest a person for terrorist activities.
They disguised themselves as Palestinians, reported the Reuters agency.
The border police were massively shot at, it said.
The security forces returned fire from the attackers.
There were no injuries on the Israeli side.
According to Palestinian sources, the men were shot by snipers.
Israel had conquered the West Bank and East Jerusalem, among others, during the Six Day War in 1967.
The Palestinians want to establish an independent state of Palestine in the area with East Jerusalem as its capital.