An Israeli missile has struck a car in Gaza City, killing at least two of its occupants and wounding two others, Palestinian officials say.
The attack reportedly killed militants from the al-Aqsa Martyrs Brigade.
An Israeli army official said the strike targeted militants who had fired a rocket at Israel.
Five militants and a child died in an Israeli strike on Gaza on Friday - the biggest such attack since the Hamas militant group formed a new government.
The boy killed had been travelling in a car with his father, a leading militant from the Popular Front for the Liberation of Palestine.
At least 12 people were injured in the attack.
An Israeli army spokesman said Saturday's attack came after militants were spotted firing rockets into Israel.
"They fired the rockets, they got into the car and we hit the car," the spokesman told the Reuters news agency.
The strike took place in the Shijaia neighbourhood of Gaza City, near the boundary with Israel.
Palestinians often fire crude rockets into Israeli territory but these rarely cause any casualties.
Six Palestinians were killed on Friday evening in the deadliest attack levelled by Israeli forces in Gaza since the Hamas-led government took office last week.