Eight rockets and mortars fired from Gaza have hit towns in southern Israel, with one house being severely damaged in Sderot, Israeli rescue service workers have said.
No one was injured in the attack, which began at about 7am (0500GMT) on Sunday, two days after the official end of a truce between Israel and Hamas, which controls the Gaza Strip.
A migrant worker was wounded by shrapnel in a separate rocket attack on a Kibbutz, an Israeli farming co-operative.
The Islamic Jihad group claimed responsibility for the attacks.
Air raid launched
Ayman Mohyeldin, Al Jazeera's correspondent in the Gaza Strip, said that the Israeli military launched an air raid into Gaza, targeting a rocket firing squad.
There were no immediate reports of casualties.
More than 30 rockets were fired from Gaza into Israel on Saturday, while one Palestinian fighter was killed in an Israeli air raid.
Those respective attacks came a day after a six-month-old ceasefire between Israel and Hamas ended.
Tel Aviv has said will not take military action if the Palestinian fighters hold their fire, but it has said it will begin a dedicated military operation in Gaza if rocket fire barrages continue.
"The scenarios are clear, the plans are clear, the determination is clear, and so are the ramifications of each of the steps. A responsible government is not happy to go to war, but does not evade it," Ehud Olmert, Israel's prime minister, said in his weekly cabinet meeting on Sunday.
In recent months, Israel has maintained a crippling blockade of Gaza in what it calls a response to rocket fire from Palestinian squads.
Human rights groups have criticised the Israeli restrictions, saying that they amount to collective punishment of the Gaza Strip's 1.4 million Palestinians.