Four people were wounded Tuesday, one of the moderately, as Hamas fired a barrage of Qassam rockets at the western Negev.
At least 21 rockets were fired at Israel on Tuesday, at least eight of which hit the western Negev town of Sderot.
A 44-year-old woman was moderately wounded and her 4-year-old son lightly hurt when a Qassam rocket scored a direct hit on their Sderot home.
Two people were lightly wounded in additional rocket strikes in the town.
A spokeswoman for Barzilai Hospital in Ashkelon said some 30 individuals were brought to the hospital and treated for shock.
Defense Minister Amir Peretz held security consultations with the participation of senior Israel Defense Forces and Shin Bet officials in order to discuss the escalation on Tuesday. Sderot schools have canceled classes for Wednesday.
"Israel cannot nor will it tolerate these continued Qassam rocket attacks on its citizens," said David Baker, an official in the Prime Minister's Office. "Today we saw direct hits on an Israeli home and a school."
"Hamas continues to lead the way in stirring and perpetrating terrorist attacks of this type," he added. "Israel is ready to take whatever measures are necessary to prevent this and safeguard the lives of its citizens."
One rocket hit another house in Sderot, one hit a schoolyard in the town and the four others hit open areas. There were no reports of injuries.
Another two rockets hit an open area in the Sha'ar Hanegev Regional Council, one of which caused a fire. Two rockets hit open areas near Sderot, causing no injuries or damage.
Two more rockets were fired at Israel late Tuesday night, one of which hit the Sderot area.
Earlier Sunday, Palestinian militants fired a Qassam rocket at the western Negev, although it could not be determined where the rocket struck.
Following the Qassam attacks, the Israel Air Force fired into uninhabited areas of northern Gaza. There were no immediate reports of injuries.
An army spokeswoman described the fire as a "deterrent" aimed at preventing militants from firing additional rockets at towns near the Gaza border.
According to Hamas' armed wing, it fired the rockets to mark Nakba Day, on which Palestinians commemorate what they call the catastrophe of Israel's creation.
The group added that the rocket attack was also designed to shift the focus to Israel after days of deadly factional fighting in Gaza between Hamas and Fatah that has left at least 20 people dead.
Tuesday's rocket fire marks the second time in recent weeks that Hamas has violated the tenuous Gaza Strip cease-fire. On Israel's Independence Day, Hamas fired an intense barrage of rockets and mortars at southern Israel.
Following that attack, Palestinian Authority Chairman Mahmoud Abbas vowed that Hamas would not repeat its violations of the truce.
The security cabinet approved broader military action in the Gaza Strip to counter the ongoing Qassam rocket fire.
Currently, the army will be allowed a freer hand in two types of activities: operating along the border fence and targeting Qassam rocket crews.
In some instances the army will be allowed to carry out operations deeper in Palestinian territory. Currently, such activities are restricted to uncovering tunnels and securing areas where explosive devices have been identified.
Regarding the Qassam rocket crews, authorization will be given to target them at earlier stages of preparation. Currently, crews are targeted only when they are about to launch rockets. Authorization for targeting rocket crews at earlier stages will depend on whether an IDF operation would endanger the lives of Palestinian civilians near the militants.
Also, a process is expected to be approved for isolated assassinations of Islamic Jihad militants involved in Qassam rocket launches.
In recent months, Israel has not tried to carry out assassinations in the Gaza Strip.
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