Four Palestinians have been killed in two separate Israeli air raids in the southern Gaza town of Rafah, security officials and health workers have said.
Mohammed Harb - a leader of the Ezzeddine Al-Qassam Brigades, the armed wing of Hamas - and one of his deputies are believed to be among the dead.
The car they were travelling in was completely destroyed in the attack on Friday morning.
Two other members of the Al-Qassam Brigades were killed overnight in another Israeli raid.
Hamas confirmed the second strike was aimed at two of its local commanders in the area.
An Israeli army spokeswoman said the military had carried out both air raids on Friday, saying that the targets had been "terror operatives".
Rafah became the focus of international attention on Wednesday when tens of thousands of Palestinians poured into Egypt from the Gaza Strip to stock up on food and fuel which is in short supply due to an Israeli blockade.
The border wall was breached in a series of explosions that are believed to have been carried out by Hamas.