At least 19 Palestinians were said to have been wounded in the Gaza strip as a result of air strikes launched by Israel on Monday after militants launched mortars and rockets into Israeli territory.
Among the wounded were seven children, two women and four militants, according to officials from Hamas, the Islamist group that controls Gaza.
Hamas has stepped up rocket fire at Israel after a lengthy hiatus since the war of two years ago, claiming responsibility for the firing of more than two dozen mortars and rockets at the weekend.
The Israeli military confirmed one of the air raids, saying that several Hamas-affiliated militants were targeted in northern Gaza, as well as a tunnel used to smuggle weapons.
Witnesses in Gaza said Israeli warplanes fired a missile after three mortars were shot at Israel, and the Israeli missile landed harmlessly in a bin for animal feed.
Israel fired four other missiles at as many targets later in the evening, aiming at a Hamas security compound in Gaza City, a training camp north of the city, and a brickworks and metal foundry in northern Gaza, witnesses said.
Hamas fired two rockets into southern Israel on Sunday, a day after Palestinian militants fired more than 50 mortar shells into Israel in the the heaviest Palestinian barrage since a major Israeli military offensive in Gaza two years ago. In the evening, militants in Gaza fired another rocket into southern Israel, exploding near the city of Ashkelon. No one was hurt.
Medical officials in Gaza said on Sunday that the bodies of two Palestinian men who were killed overnight along the border had been recovered. The Israeli military said soldiers spotted two Palestinians crawling towards the border with what appeared to be a bomb. Soldiers called on them to stop, and opened fire after they continued moving.
Most rocket attacks from Gaza since the invasion have been carried out by small militant groups, although Hamas claimed responsibility for some mortar fire on Saturday, which slightly wounded two Israelis.