Jerusalem ? 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 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.

Maher Makdad of the Palestinians’ Fatah movement rejected the Israeli claims. “I only heard lies,” he said. “I also heard an insistence on continuing these practices, because if they admitted their mistake, we could understand that they are ready to change their policies.”

Peretz denied all responsibility. “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.”

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

Palestinians inspect the area where a group of civilians were killed and injured on the beach of the northern Gaza Strip town of Beit Lahiya in this photo from Friday. On Tuesday, Israel said an investigation showed the explosion was not caused by artillery fired by the Israeli Defense Forces.

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 battle damage assessment expert Marc Garlasco 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.

Unexploded ordnance left over from the current conflict as well as from wars over the past century has been a problem in Gaza, where there are several incidents a year of Palestinians wounded in blasts.

“Our information certainly supports, I believe, an Israeli shell did come in,” Garlasco said, ruling out a land mine. Garlasco, formerly of the U.S. military, was the first neutral specialist to inspect the scene. Israel is often critical of the human rights group’s findings.

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.

Palestinians replied that militants were unlikely to plant bombs at a beach teeming with hundreds of people every weekend.

Palestinian lawmaker Saeb Erekat, who is close to President Mahmoud Abbas, 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.”