The Israeli airforce launched three raids on targets in the Gaza Strip in the early hours of Tuesday morning, hitting two “rocket launching sites used by militants” and a weapons storage facility, the military said in a statement.
Palestinian security sources and witnesses told AFP news agency that there were no casualties and the raids hit an uninhabited area to the west of Gaza City.
The strikes followed a warning on Monday warned that it would hit hard at Palestinian fighters who launch rockets into the Jewish state.
The Israeli army said it had scored direct hits on the targets.
The Gaza fighters indicated late on Monday that they were ready for a truce but there was no immediate response from Israel.
According to Reuters, leaders of Hamas, the Islamist faction that controls Gaza, met with Islamic Jihad and other groups and said they would respond according to the way Israel acted - a formulation used in previous flare-ups to offer a ceasefire.
The Israeli targets included a training camp of the Ezzedine al-Qassam Brigade, the military wing of the Palestinian Islamic movement Hamas, the sources said.
An Israeli army spokesman said the planes attacked an arms dump and two rocket launch sites.
The air raids came hours after Gaza gunmen on Monday fired six rockets at southern Israel, one of which exploded next to a house.
The number of rockets fired on Monday represented a significant drop from a day earlier, when dozens of missiles crashed into southern Israel, prompting Israel to stage a series of overnight raids.
But it was unclear if the slowdown was a step towards a more decisive truce, or a lull.
Palestinian fighters began launching rockets into Israel from around 7:30 a.m. on Monday.
An initial count of 11 rockets was later revised down to six by the military, with the same number confirmed by the police. Two of them were intercepted by the Iron Dome anti-missile system.
One rocket landed in Netivot where medics said they treated 26 people for shock.
The latest flare-up began on Saturday night and has claimed the lives of six Palestinians, as armed groups fired scores of rockets at Israel, wounding eight.
Monday’s rocket fire was claimed by the Popular Front for the Liberation of Palestine, the Democratic Front for the Liberation of Palestine and the Popular Resistance Committees.
Israel’s top military officials were said to be weighing whether to launch a stronger response to the flare-up, and Defense Minister Ehud Barak warned that efforts to stamp out rocket fire would intensify.
“These are very important days.. in light of the ongoing activity against Hamas and terror organizations in Gaza, which is likely to intensify and expand,” he said, quoted by his office.
Prime Minister Benjamin Netanyahu, touring southern Israel with foreign diplomats, warned that “the world must understand that Israel has the complete right and the obligation to protect its citizens.”
“We shall not sit with our arms folded in the face of repeated, almost daily, attacks on our citizens,” he added. “We shall act to stop it.”
U.S. ambassador Dan Shapiro, writing on Facebook, said “the United States supports Israel’s right to defend itself and its citizens from these attacks.”
Egyptian security sources said Cairo was attempting to broker a ceasefire, with gunmen from the ruling Hamas movement and from Islamic Jihad saying they would observe any truce “provided Israel commits to doing the same.”
On Saturday evening, gunmen fired an anti-tank missile at an army jeep, injuring four soldiers. The Israeli military hit back, killing six Palestinians, and wounding more than 30.
European Union foreign policy chief Catherine Ashton on Monday urged both sides to “refrain from exacerbating the situation.”
The violence, which comes amid an Israeli election campaign, raised the specter of a broader Israeli military campaign similar to its 22-day Operation Cast Lead, launched in December 2008.
That campaign claimed the lives of 1,400 Palestinians -- half of them civilians -- and 13 Israelis, 10 of them soldiers.