An explosion flattened a house in the Gaza Strip on Thursday, killing seven people. After blaming Israel and unleashing a barrage of rockets and mortars, Hamas suggested the blast was accidental, not an Israeli attack. By then Israel had carried out an airstrike aimed at a Gaza rocket squad, killing a Palestinian. The violence threatened to scuttle Egyptian cease-fire efforts as they approached the finish line. A key Israeli envoy, Amos Gilad, was in Egypt trying to wrap up a deal, but there was no announcement of results.

An Israeli army spokeswoman said the military was not operating in the area of the house at the time of the blast.

"We deny any connection to this incident," Maj. Avital Leibovich said.

Hamas spokesman Abu Obeida said there would be an investigation of the blast and the results would be made public.

The statement was taken as a Hamas acknowledgment that the blast was probably accidental, not an Israeli attack. Dozens of militants have been killed while handing explosives in recent years.

The blast shook the town of Beit Lahiya in northern Gaza, about a mile from the Israeli border.

Ambulances rushed to the scene, and residents of nearby homes brought shovels and bulldozers to help dig people out. Three people covered in blood were carried out on stretchers and hurried into ambulances that sped them away to a hospital.

Hamas said seven people were killed, including a 4-month-old girl and a senior aide to the Hamas interior minister. Several bodies were removed from the rubble. Among the dead were five militants, Hamas said.

The owner of the house, Hamas area commander Ahmed Hamouda, was not there at the time of the explosion.

Cars parked nearby were destroyed and covered with dust, and windows of neighboring houses and shops were shattered. Electricians tried to disconnect live wires in the wrecked house.

"It was a huge explosion," said Majid Abu Samra, a neighbor.

Shortly after the explosion, Hamas said it fired a barrage of mortar shells and rockets toward southern Israel in retaliation. Israel's rescue service said a 59-year-old woman was wounded when a rocket struck a home on an Israeli communal farm.

Mark Regev, an Israeli government spokesman, issued an angry response, noting the rocket barrage came just a day after Israel publicly endorsed the Egyptian truce effort. It proved that Hamas "is committed to violence, terror and murder," he said.

Israeli troops Thursday killed two Palestinian militants in a clash in northern Gaza, and Dr. Moaiya Hassanain of the Gaza Health Ministry said another person was killed in an Israeli airstrike in southern Gaza. The Israeli military said aircraft hit a rocket squad.

Israeli government and security officials said Israel was willing to give the Egyptian mediation efforts about two more weeks to succeed, but if those efforts fail, it would invade Gaza.

Egypt is acting as middleman in the truce talks because Israel has no contacts with Hamas, which has killed more than 250 Israelis in suicide attacks and rejects the Jewish state's right to exist.

Major points of contention remain, most prominently, Israel's demand to link the truce deal to the release of an Israeli soldier held captive by Hamas for two years, and a Hamas demand that Israel open Gaza's border crossings.

Israel blockaded Gaza a year ago after Hamas, which has killed hundreds of Israelis, violently seized control of Gaza from security forces affiliated with the moderate Palestinian president, Mahmoud Abbas.

The closure has prevented the vast majority of Gaza's 1.4 million people from leaving and has led to widespread shortages of fuel, electricity and basic goods.

Written By IBRAHIM BARZAK

Email To A Friend