A Palestinian rocket slammed into a college campus in this southern Israeli town on Wednesday, killing a student, and another exploded near a hospital in a coastal city farther away, raising the likelihood of a new wave of fighting between Israeli forces and Palestinian militants in neighboring Gaza.

Hamas claimed responsibility for the deadly rocket attack, which came after two Israeli airstrikes killed seven people in Gaza, including two senior commanders in the Hamas rocket operation.

After nightfall, a third Israeli strike aimed at a rocket squad killed two youngsters leaving a mosque, Palestinians said. The Israeli military said it carried out the airstrike but had no knowledge of civilians being hit.

In all, at least 40 rockets were fired at Israel on Wednesday, the military said, many more than the average of daily barrages that have disrupted life in the region. Associated Press pictures showed rockets being fired from a densely populated area of northern Gaza.

One rocket exploded in a parking lot at Sapir College. Israeli officials said a student, about 30 years old, was killed by shrapnel that struck his heart. Israeli TV stations showed a second man being carried on a stretcher with wounds to his legs. The student was the first Israeli killed by a rocket since May, when two died in separate attacks.

At nightfall, four rockets exploded in the Israeli coastal city of Ashkelon, including one near the city's main hospital, police said. No one was hurt. Ashkelon is 10 kilometers (6 miles) north of Gaza.

The fatal attack intensified calls in Israel for a large-scale ground attack in Gaza aimed at clearing the border area of rocket squads, though previous incursions have halted the salvos only briefly. Prime Minister Ehud Olmert, who is visiting Japan, has ruled out such an invasion for now.

Battered residents were both angry and resigned. "We knew this was coming. It's a shame that it happened. This is a difficult day," Sderot's mayor, Eli Moyal, told Army Radio.

Students at the college tried in vain to revive the stricken student, who had a gaping, bloody hole in the left side of his chest.

David Barnan, head of the college's students association, said he was shocked by what he saw. "I can't put it into words," he told Army Radio. Barnan demanded that the government carry out its pledges to reinforce buildings at the college, but he remained defiant.

"This is our country," he said. "We will stay alive, we continue our studies, we will continue to do all the things we need to do, and speaking for myself, I can say we're not afraid of anyone."

Cabinet Minister Meir Sheetrit called for an intensified campaign to target Gaza militants. "If it were up to me, I would hit everything that moves with weapons and ammunition," he told Army Radio. "I don't think we have to show pity for anyone who wants to kill us."

Early Wednesday, an Israeli aircraft blew up a minivan carrying Hamas gunmen, killing five militants, including two key masterminds of rocket attacks on Israel, Hamas said.

Burned bodies in camouflage uniforms were visible in the twisted white minivan. Hamas officials said the dead included a senior engineer who built rockets and commander who led a rocket squad. Two other Hamas members were wounded in the airstrike, according to Hamas and health officials.

Hamas spokesman Taher Nunu called the airstrike "a new Israeli crime."

Israeli security officials said some of the militants killed in the airstrike had trained in Iran and Syria, without elaborating.

Later Wednesday, an Israeli airstrike in northern Gaza, a frequent launching ground of the rocket squads, killed two people. Palestinian officials said one of the dead was a civilian farm worker.

The body of another Palestinian militant killed in central Gaza overnight was brought to the hospital in Gaza on Wednesday morning.

A poll published Wednesday, before the fatal rocket attack, showed that a majority of Israelis favor talks with Hamas stop the barrages and win release of a soldier captured in 2006. Israel's government has ruled out talks with Hamas, which is sworn to Israel's destruction.

In the West Bank on Wednesday, undercover Israeli troops killed a militant and wounded a bystander in a daylight raid in the city of Nablus, Palestinians said. The dead man belonged to a militant offshoot of the Fatah movement led by President Mahmoud Abbas. The Israeli military confirmed it had carried out an operation but gave no details.

In addition to its military strikes, Israel has imposed tough economic sanctions on Hamas-ruled Gaza, allowing only basic humanitarian goods into the area.

The sanctions have caused widespread shortages. On Wednesday, the area's main water provider urged residents to boil drinking water, citing a shortage of purifying chlorine.

The Coastal Municipality Water Utility said there was a "major concern over a health disaster due to possible contamination of the drinking water" and appealed to the international community for help.

An Israeli military spokesman said Palestinians did not make a request for chlorine until Wednesday.