Two men were killed in a gun battle in the northern town of Beit Hanun on Saturday.
The men belonged to the Al Aqsa Martyrs Brigades, an armed offshoot of Palestinian leader Yasir Arafat's Fatah movement, Palestinian witnesses said.
In southern Gaza, an Israeli aircraft fired a missile on Saturday morning at a group of Palestinians in the town of Khan Yunis, Aljazeera learnt.
The two dead, Imad Badr, 24, and Fakhir Fakhir, 22, were members of the Palestinian national security force, security sources said.
The Israeli military said it had targeted two armed gunmen.
Violence in Gaza has soared ahead of Israeli Prime Minister Ariel Sharon's planned withdrawal of troops and settlers next year from the territory captured in the 1967 Middle East war.
At least 102 Palestinians, have been killed in the offensive with some 200 tanks and armoured vehicles, the biggest thrust into Gaza since a Palestinian uprising began in 2000.
The offensive followed the killing of two Israeli children by a Hamas rocket in a border town on 29 September. Three Israelis have died in fighting in Gaza since then.
Since the start of the Palestinians' four-year-old intifada, 4464 people have been killed, including 3436 Palestinians and 954 Israelis.
On Friday four Palestinians including two teenagers and a nine-year-old girl were killed by Israeli fire in the northern Gaza Strip.