Israeli warplanes have struck Hamas positions in Gaza after Palestinian militants fired dozens of rockets and mortars at southern communities, the military said.
It was the biggest flare-up between the sides in weeks, although no casualties were reported in Israel or Gaza.
Israel said it targeted about 25 Hamas targets overnight in response to the heavy Palestinian fire.
Fawzi Barhoum, a spokesman for Hamas, praised the rocket attacks, calling them “a legitimate right that bombing is met with bombing”, but did not take responsibility for them.
The Israeli military said Palestinians fired about 45 rockets and mortars at Israel. Seven were intercepted by the Iron Dome defence system and at least three fell prematurely, landing inside Gaza, it said.
Some rockets exploded inside Israel, damaging property. Channel 10 TV showed footage of Israeli houses and cars peppered with shrapnel and said one mortar exploded next to a nursery.
Israeli police said its bomb disposal unit dealt with a rocket that landed in a populated area.
“The Hamas terror organisation targeted Israeli civilians throughout the night with a severe rocket attack and is dragging the Gaza Strip and its civilians down a continually deteriorating path,” the military said.
Tensions are high along the Gaza border after months of weekly mass rallies led by the Islamic militant group that rules the territory turned violent.
More than 100 Palestinians have been killed by Israeli fire since they began.
Israel says it is defending a sovereign border and nearby communities, and accuses Hamas of using the protests as cover for attempts to breach the border fence and carry out attacks.
The protests are aimed in part at drawing attention to the decade-long Israeli-Egyptian blockade imposed on the territory after Hamas, a group sworn to Israel’s destruction, seized control of Gaza.
Israel has also been battling large fires caused by kites and balloons rigged with incendiary devices or burning rags, launched by Palestinians from Gaza, which have destroyed forests, burned crops and killed wildlife and livestock.