A missile struck Tal al-Hawa district, north of Gaza city, on Monday, reported Aljazeera's correspondent.
The targeted vehicle was a small pickup truck with official Palestinian Authority licence plates, witnesses said.
On Sunday, a senior Gaza leader of the Palestinian resistance group Hamas was killed by an Israeli missile strike on his car.
Hamas earlier on Monday retaliated with rocket fire on Israel.
Israel has killed scores of Palestinians including resistance leaders and fighters in air strikes since a four-year-old Palestinian uprising began.
Tension has escalated in Gaza since Israeli Prime Minister Ariel Sharon announced his plan to withdraw troops and settlers by the end of next year from the narrow coastal strip captured by Israel in the 1967 war.
Palestinians believe that former Israeli general is seeking to crush all resistance before the withdrawal which would enable him to claim a military victory.