Thousands of Palestinian mourners wept with sevenyear-old Huda Ghalya as she kneeled to kiss her dead father before he, her mother and three siblings were buried in northern Gaza.

The five, including a four-month-old, a three-year-old and a 10-year-old, were among the seven killed during a seaside outing on Friday after Israeli gunboats shelled the area to curb cross-border rocket fire. Twenty people were wounded.

"Please do not leave me alone, " said Huda, who had been swimming in the Mediterranean when the blast tore up the beach.

A spokesman for Hamas' Izz el-Deen al-Qassam brigades said they had resumed attacks against Israel in response to the shelling, firing 11 rockets and 12 mortar bombs from Gaza.

The Israeli army said it identified four impacts inside Israel, which caused no casualties or damage.

With peacemaking now an even more remote prospect, the Palestinian Authority president yesterday set 26 July as the date for a controversial referendum on a statehood plan that implicitly recognises Israel. Mahmoud Abbas made the announcement in an official decree. Hamas rejected the proposal, saying such a vote would be illegal.

The declaration of the end of Hamas's ceaseire raised the prospect of a new wave of bloodshed. Hamas militants suspended a campaign of deadly suicide attacks on Israelis with a February 2005 cease-fire, and have largely stuck to the truce. The Islamic group now leads the Palestinian government.

"The earthquake in the Zionist towns will start again and the aggressors will have no choice but to prepare their coffins or their luggage, " the Hamas militants said in a leaflet. "The resistance groups . . . will choose the proper place and time for the tough, strong and unique response."

The Israeli artillery attack was part of a wider aerial and artillery bombardment of suspected Palestinian rocket-launching sites that killed 10 people yesterday.

The violence fuelled tensions already high over an Israeli air-strike that killed a militant commander in the Hamas-led government on Thursday.

Palestinian President Mahmoud Abbas condemned the attack on the beach as a "genocidal crime." He called for international intervention and declared a three-day period of mourning.

His rival, Prime Minister Ismail Haniyeh of Hamas, said the shelling was a "war crime" and urged an end to recent fighting between Hamas and Abbas' moderate Fatah movement.

The killings had raised questions about whether Abbas would go ahead with a referendum on establishing a Palestinian state alongside Israel despite pleas from Hamas to hold off.

Abbas is eager to restart stalled peace talks with Israel, and was expected to formally announce a 31 July date for the referendum. An official close to Abbas said late yesterday that the president would make his announcement soon. Israel said its attacks were aimed at areas that Palestinian militants used to fire homemade rockets at Israel.