The militant rocket landed in open ground and caused no damage or injuries, the army said. No casualties were reported in Gaza following the air strike, which struck a Hamas training facility.

An Israeli army spokesman's statement said the air strike was aimed at "terror infrastructure in the Northern Gaza Strip. Hits were confirmed."

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.

Air raid sirens sounded throughout Ashkelon, a city about 10 km (6 miles) north of Gaza with a population of about 120,000.

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.

"The Jews will never enjoy security and safety as long as we are alive," the group said in a statement.