There were conflicting reports on the cause of death of Abu Yousef al-Guga, the commander of the Popular Resistance Committees in Gaza.
While witnesses said he was killed in an Israeli airstrike, others said he died in a car bomb attack on Friday.
Earlier report said that an Israeli aircraft fired a missile at al-Guga's car as he drove to one of the mosques in northern Gaza City for Friday prayer.
But senior security sources told Xinhua that a booby-trapped car on roadside exploded and directly hit his car.
An Israeli army spokesman also said that Israel had nothing to do with al-Guga's death.
Abu Abeer, spokesman of the militant group involved in firing homemade rockets at southern Israel, told reporters that Al-Guga was killed in the Israeli targeted killing.
Al-Guga was killed shortly after a Palestinian suicide bomber blew his explosive-laden car at the settlement of Kadomim near the northern West Bank town of Qalqilia on Thursday night, killing four Israeli soldiers.
Source: Xinhua