Israel's military says it has carried out an airstrike in the northern Gaza Strip in response to a rocket fired from Hamas-controlled territory into southern Israel.
No casualties were reported Sunday from either strike. Air raid sirens sounded throughout Ashkelon, a city about 10 km (6 miles) north of Gaza with a population of about 120,000.
Israel said it is closing its border crossings into Gaza.
Sporadic rocket fire from Gaza in recent weeks has broken a lull in cross-border violence since a 50-day Israeli war against Hamas ended with an Egyptian-brokered truce last August.
A Jihadist Salafi group, the "Omar Brigades," sympathizers with Islamic State, claimed responsibility for firing the rocket at Ashkelon. It also claimed the previous recent firings at Israel.
The group said the rocket aimed at Ashkelon was in solidarity with Palestinian prisoners held in Israeli jails, and their own members incarcerated in Hamas-controlled jails in Gaza.
Some material for this report came from Reuters.