Defense Minister Amir Peretz said Tuesday that Israel was not responsible for a blast that killed eight Gaza beachgoers, rebuffing Palestinian accusations that blamed an Israeli artillery round.

An Israeli inquiry concluded that the blast was caused by an explosive buried in the sand, not from Israeli shelling on the afternoon of the Palestinian family's beach picnic.

It was not clear how the explosive got there, or whether it might have been an unexploded Israeli shell from an earlier military barrage. Peretz did not address that issue in his remarks. Israel has been claiming that Hamas militants planted a device to set off against Israeli commandos.

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"We have enough findings to back up the suspicion that the intention to describe this as an Israeli event is simply not correct," Peretz said at a Tel Aviv news conference on the inquiry's findings. "The accumulating evidence proves that this incident was not due to Israeli forces."

Palestinians angrily rejected the findings, saying militants were unlikely to plant bombs at a beach teeming with hundreds of people every weekend.

The bloody images of dead Palestinian civilians and wailing survivors on the beach kindled anger against Israel that has swept around the world.

The seaside carnage contributed to a sudden spike in Israeli-Palestinian violence. After the beach blast — and Israeli forces' killing of a top Gaza militant — Hamas called off a 16-month cease-fire that had significantly reduced casualties on both sides.

Human Rights Watch military expert Marc Garlasco, the first independent analyst to inspect the scene, said he examined the shrapnel on the beach, saw the civilians' injuries and concluded the blast was caused by an Israeli shell. He held open the slim possibility that it was planted there by Palestinian militants, although fragment patterns did not back that.

"Our information certainly supports, I believe, an Israeli shell did come in," he said, ruling out a land mine.

According to Israeli findings, shrapnel taken from two wounded Palestinians who were evacuated to Israeli hospitals showed that the fragments were not from the 155-millimeter shells used by Israeli artillery.

Showing aerial photographs and film, the head of the Israeli inquiry, Maj. Gen. Meir Klifi, declared: "There is no chance that a shell hit this area. Absolutely no chance."

Israel has been pounding northern Gaza with hundreds of artillery shells for weeks, trying unsuccessfully to stop Palestinian militants from setting up and launching homemade rockets at Israel.

In recent days, Israeli commando forces have entered Gaza to ambush rocket squads.

Palestinians rejected the possibility that their own explosives caused the fatal blast.

"This is a false allegation, and the Israeli occupation state is trying to escape from shouldering its responsibility by accusing Palestinians without evidence or any proof," said Ghazi Hamad, a spokesman for the Hamas-led Palestinian government.

"The eyewitnesses and the evidence that we have confirm that the massacre is the result of Israeli shelling, and the allegation about land mines planted by Palestinians is baseless," he said.

Palestinian lawmaker Saeb Erekat, who is close to President Mahmoud Abbas, a Hamas rival, called for an international inquiry. He complained that Israel was trying to blame the Palestinians and warned, "this means that this crime could re-occur."

Klifi said the explosion took place between 4:47 p.m. and 5:10 p.m., and no Israeli shells were fired then.

The blast occurred on the outskirts of the town of Beit Lahiya, not far from where Palestinian militants frequently fire rockets toward Israel. The shore is frequented by hundreds of Palestinian beachgoers on Fridays, a rest day in Gaza.

The army has accounted for five of six of the shells that it fired in the area Friday evening before the beach explosion, Klifi said. None of them exploded nearby. The one shell that is not accounted for was fired before the five others — more than 10 minutes before the blast that killed the Palestinians, he said.