In response to a rocket fired earlier from the Palestinian territory, Israeli aircraft hit several sites in the Gaza Strip on Sunday, Israel's military said.

Immediate reports of injuries were not available.

Although several militant groups are operating out of the Palestinian enclave, Israel holds Gaza's Hamas rulers accountable for any rocket fire from the region and in retaliation, usually strikes Hamas targets.

The Israeli military said in a statement that two rocket ammunition production facilities, underground infrastructure, and a Hamas naval force training compound were struck by fighter jets and assault helicopters.

Palestinian militants in Gaza fired a rocket at Israel late Saturday, setting off air-raid sirens in Ashkelon, a southern Israeli city, the Israeli military said.

The Israeli police confirmed that the rocket had caused damage to a structure in the Ashkelon region, about 10 kilometers (6 miles) north of Gaza, but no injuries were reported. The Israeli media said that the rocket hit a factory and caused damage.

Israel and Hamas, an Islamic terrorist group seeking the destruction of Israel, are bitter rivals who after Hamas seized power in Gaza in 2007, have fought three wars and countless skirmishes.