The US Secretary of State has pressed Israel to seriously consider an Egyptian ceasefire plan for Gaza as the UN Security Council struggled to find a common approach.

Condoleezza Rice spoke by telephone to Israeli Prime Minister Ehud Olmert and Foreign Minister Tzipi Livni and said she had detailed discussions with them on the conditions on the ground in Gaza as well as the Egyptian initiative.

"We're supporting that initiative. I've been in very close discussions with my Arab colleagues but also with the Israelis about the importance of moving that initiative forward," she said.

The plan offered by Egyptian President Hosni Mubarak seeks to end the 12-day offensive that Israel launched with the declared aim of suppressing rocket fire from Hamas Islamist militants on its southern towns.

In Israel, officials said they accepted the "principles" of the proposal, but the details needed to be worked out.

Ms Rice said she had also spoken to the Israelis about the need for a pause in violence, as happened on Wednesday for three hours, to allow for humanitarian aid to get through.

"That needs to be repeated again and again," she said of the three-hour truce.

Meanwhile, the Israeli cabinet has deferred a vote on whether to order its armed forces to storm the Gaza Strip's urban centres.

The postponement allows Israel to keep its forces in readiness while leaving room to manoeuvre if Franco-Egyptian efforts to secure a truce with Hamas are successful.

Israeli ground forces entered the Gaza Strip on Saturday after an aerial bombardment. More than 760 Palestinians, including 130 militants, have been killed in the 12-day-old offensive while seven Israeli soldiers and three civilians have died.

On Tuesday, 42 Palestinians were killed by Israeli airstrikes at the UN-run al-Fakhora school in Jabalya refugee camp, where hundreds of terrified Palestinians were hiding from fierce fighting. Two other UN-run schools in Gaza were also hit, causing fatalities.

Military analysts believe Israeli forces would be severely challenged by combat in Gaza's congested kasbahs and alleyways, where air support would be irrelevant and where Palestinian gunmen could mount ambushes.

An Israeli source said military leaders were content with the initial ground sweep but were disappointed by what they saw as relatively little Palestinian resistance.

The source said: "The assumption was that our forces could draw out the enemy into open areas where they could be eliminated, but they didn't come out in the number we expected. Taking the fight into the populated areas would be much tougher."

Earlier, a three-hour lull in fighting took place in a bid to get humanitarian aid to victims of the conflict.

But John Ging, director of operations in Gaza for the United Nations Relief and Works Agency (UNRWA), said the region has become "hell on earth" for its 1.5 million inhabitants and the lull in fighting was insufficient, given their needs.

Meanwhile, French President Nicolas Sarkozy sparked confusion when his office released a statement saying Israel and Hamas had accepted an Egyptian truce plan.

The statement said: "The president is delighted by the acceptance by Israel and the Palestinian Authority of the Franco-Egyptian plan presented last night in Sharm el-Sheikh by (Egyptian) President (Hosni) Mubarak.

"The head of state calls for this plan to be implemented as quickly as possible for the suffering of the population to stop."

Israel responded by saying it viewed talks on the proposal "positively" but stopped short of accepting Egypt's plan.

US President-elect Barack Obama, who has avoided commenting on foreign policy matters, has said he will "engage immediately" in the Gaza situation once he takes office on January 20, repeating that he was "deeply concerned".

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