Israeli helicopters have fired at least two missiles into a refugee camp in the Gaza Strip, Palestinians say.
A house in the Gaza town of Deir al-Balah was hit on Thursday
Security sources are reported as saying the missiles hit a warehouse in the Mughazi refugee camp in central Gaza.
The strikes come a day after an Israeli incursion into the central Gazan town of Deir al-Balah, which left four Palestinians dead.
Sixteen Israelis were killed when suicide bombers targeted two buses in southern Israel on Wednesday.
Witnesses said Friday evening's missile strike set the warehouse building on fire.
It was not immediately known if there were casualties.
The Israeli army has targeted the building before, saying it is used by Hamas militants for making weapons.
Its owners, said to be a prominent Palestinian family, have denied the allegations and say they use the building to store wood for construction.
Earlier on Friday, two Palestinian men were killed after they were shot at by Israeli troops as they entered a closed area near the perimeter fence around Gaza.
It is thought the explosives they were carrying were detonated by Israeli gunfire.
The Israeli army moved into Deir al-Balah on Thursday to uncover a tunnel reportedly dug by militants either to hide weapons or to launch an attack on a nearby Jewish settlement.
Four Palestinian teenagers are known to have been killed during the incursion.
Israel vowed to target Hamas leaders, after the militant group claimed responsibility for the attacks on two buses in the southern Israeli town of Beersheba.
Hamas said the near-simultaneous attacks that left 16 dead were to avenge the deaths of two of its leaders.