Israeli aircraft bombed four targets in Gaza early Thursday, after Palestinian militants for the first time in weeks launched a relatively long-range missile at a southern Israeli city dpa reported
The Russian-type Grad rocket landed in an open field near the port city of Ashdod, on the coast north of Gaza, an Israeli military spokesman said.
The spokesman said there was one launch, which triggered sirens in a number of southern Israeli communities, causing some to believe there was more than one. Israeli media had reported about a volley of missiles.
"It was just unusual because it was a long-range launch after a relatively quiet period," the military spokesman in Tel Aviv told dpa.
The targets bombed by Israel in retaliation included three areas in central Gaza used by militant groups, and a building in the south of the strip, where the Israeli military said weapons were stored.
There were no immediate reports of injuries on either side, but it was the first exchange since Israel and Hamas, the radical Islamist group ruling Gaza, agreed to a prisoner exchange earlier this month.
Hamas last week freed Gilad Shalit, an Israeli soldier it had held hostage for more than five years, for 477 Palestinian militants. Israel is to free another 550 Palestinian prisoners in some two months' time.
It was not immediately clear which militant group fired the Grad rocket at Ashdod.
"The IDF (Israel Defence Forces) will not tolerate any attempt to harm Israeli civilians and IDF soldiers," a military statement said.
The statement included a standard phrase that it held Hamas, which rules Gaza, responsible for any rocket and mortar fire from Gaza, regardless of which group carried it out.