A barrage of rockets from Gaza hit Israel overnight, the army said Saturday, with Israel retaliating with dozens of strikes in a flareup that could jeopardize truce efforts, AFP reported.
Another rocket was fired from the Palestinian territory on Saturday morning, setting off sirens in nearby Israeli communities, before being shot down by Israel's Iron Dome air defense system.
The rocket fire began late Friday, just hours after five Palestinians were killed during renewed clashes on the Gaza-Israeli border.
The biggest rocket attacks in months came despite talk of progress towards an Egyptian-brokered deal to end months of often violent protests along the border in return for an easing of Israel's crippling 11-year blockade.
"Overnight, dozens of rockets were launched from the Gaza Strip at communities in southern Israel," the army said, putting the exact number in a separate announcement at 30.
It said the Iron Dome intercepted approximately 10 of them, while two rockets came down inside the Gaza Strip and the others hit "open areas".
Israeli medics said seven civilians were being treated for shock.
In response to the rockets, Israeli fighter jets, helicopters and drones struck "approximately 80 Hamas targets throughout the Gaza Strip".
There were no reports of casualties in Gaza as a result of the strikes.
In Gaza City, a four-story building was completely destroyed in a strike, AFP correspondents on the scene said.
The Israeli army said it was a major headquarters for Gaza's Islamist rulers Hamas.
Hamas did not claim responsibility for the rockets, but Israel holds it responsible for any fire from the coastal enclave.
The armed wing of Islamic Jihad, the second largest militant group in Gaza and a close Hamas ally, hailed the rocket fire in a statement on Saturday morning.
The "resistance is considering expanding the response in number and type, if the enemy continues its aggression against our people," it said.
A Hamas official said late Friday Egypt was again seeking to negotiate a return to calm.
Israel and Hamas have fought three wars since 2008, and Egypt and the United Nations have been leading diplomatic efforts to avert a fourth.