Israeli warplanes fired missiles at five targets across Gaza, killing a senior commander of the Hamas military wing and wounding 11 people, the group said on Saturday.

The Israeli military confirmed the air strikes and said they came in response to a rocket attack from Gaza on the Israeli coastal city of Ashkelon on Friday. The attack on Ashkelon caused damage but no injuries.

The cross-border violence came after weeks of relative calm and raised concerns of further escalation.

Hamas' military wing, Izzedine al-Qassam, said it would retaliate for the killing of Issa Batran, 42. It identified Batran as a commander of the military wing in central Gaza and a senior rocket maker.

Hamas says eight of its supporters and three civilians were wounded in the air strikes.

The targets hit by missiles included a Hamas military training camp in Gaza City, smuggling tunnels under the Gaza-Egypt border and a shack on the outskirts of the Nusseirat refugee camp, Hamas security officials said.

Hamas seized Gaza by force in 2007, wresting control from internationally backed Palestinian President Mahmoud Abbas. The Islamic militants have been building crude rockets for the past decade, and have fired hundreds of them at Israeli border towns. However, the group has largely held its fire since Israel's military offensive against Gaza ended 19 months ago.

There has been no claim of responsibility for Friday's rocket strike against Ashkelon, a city of 120,000 located 11 miles (18 kilometers) to the north of Gaza and a short drive from Israel's main population center in Tel Aviv.

Since Israel's military offensive, small renegade groups in Gaza have occasionally fired crude short-range rockets. However, in Friday's attack, Ashkelon was hit by a military-grade Grad rocket.