Israeli warplanes have attacked targets in Gaza after missiles were fired into southern Israel on Sunday night.
At least six rockets had been fired from northern Gaza. Two were intercepted, the military said.
Hours later, Israeli aircraft hit at least three sites used by militants in the Gaza Strip, Israel said. No injuries were reported by either side.
The rocket fire followed a rise in tensions in Gaza after a militant died in a shoot-out with Palestinian police.
The Islamic Jihad faction says Raed Qassim Jundeyeih, a commander of its military wing, was killed on Saturday by police from Gaza’s governing Hamas movement, while Hamas says Jundeyeih was killed by a bullet fired from his own weapon.
Islamic Jihad are believed to have been behind Sunday night’s rocket attack on Israel, which came after a period of relative calm.
Sirens blared in a number of areas of southern Israel and Israeli media said two of the missiles, thought to be Grad rockets, were intercepted by the Iron Dome system in the Ashkelon area.
Israeli planes launched attacks in the early hours of Monday.
An Israeli army statement said “sites of terrorist infrastructure including two weapon storage facilities in the central Gaza Strip and a rocket launch site in the southern Gaza Strip” were targeted with “accurate strikes”.
BBC reporter Rushdi Abualouf said the sites hit belonged to both Hamas and Islamic Jihad.
Israel has said it holds Hamas responsible for all attacks emanating from the territory.