Updated

JERUSALEM (AP) — Gaza militants fired a rocket into the Israeli city of Ashkelon early Friday, the military said, a rare strike in a period of relative quiet.

The Israeli military said the rocket caused damage but no injuries. None of the Palestinian militant groups in Gaza immediately took responsibility for the attack.

The 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, was a regular target for Palestinian militants before Israel's Gaza offensive ended early last year. Militants have kept up limited rocket and mortar fire closer to the Israel-Gaza border, but the cities and towns of Israel's south have largely been quiet since the fighting ended.

"A Grad rocket hit in a yard next to buildings, in a heavily populated area," the city's mayor, Benny Vaknin, told Israel Radio, saying it was a "miracle" that no one was hurt. Vaknin said a warning siren that went off before the rocket hit gave residents time to take cover.

AP Television News footage showed blown-out windows in an Ashkelon apartment building.

Israel sees the strike as "very serious," Israeli Prime Minister Benjamin Netanyahu's office said in a statement. There was no immediate retaliation by Israel's military.

While Gaza militants usually fire locally produced short-range rockets, the projectiles that have hit Ashkelon in the past have typically been military-grade Grad rockets smuggled through underground tunnels on the Egypt-Gaza border.

Israeli police spokesman Micky Rosenfeld said one resident was treated for shock.

Gaza is ruled by the Islamic militants of Hamas, but most of the attacks since the offensive ended have been claimed by smaller militant groups that do not necessarily accept Hamas' authority. Hamas itself has largely refrained from launching attacks, apparently because of concerns about Israeli retaliation.

Rocket squads in Gaza targeted smaller Israeli communities close to the border for years before increasing their range to include Ashkelon, a 45-minute drive from Tel Aviv. That helped precipitate Israel's offensive in Gaza, launched at the end of 2008.

The three-week offensive was successful in dramatically reducing the number of rockets hitting Israel, but devastated the densely populated and impoverished Palestinian territory and drew international criticism.