The death toll in Gaza soared to more than 1,000 Saturday as bodies were pulled from the rubble during a 12-hour truce top diplomats urged Israel and Hamas to extend.

After the fragile ceasefire went into effect at 0500 GMT, medics began digging through the remains of hundreds of homes, and uncovered more than 100 bodies underneath, medics said.

The grim discoveries pushed the Palestinian toll in Gaza to more than 1,000 as US Secretary of State John Kerry met counterparts from Europe and the Middle East and urged that the truce be extended.

"We all call on parties to extend the humanitarian ceasefire," France's Foreign Minister Laurent Fabius told reporters after meeting Kerry and foreign ministers from Britain, Germany, Italy, Qatar and Turkey, as well as an EU representative.

"We all want to obtain a lasting ceasefire as quickly as possible that addresses both Israeli requirements in terms of security and Palestinian requirements in terms of socio-economic development."

There was no immediate response from Hamas, but Israeli public radio cited a senior Israeli official as saying the Jewish state was open to extending the truce if it could continue to destroy militant tunnels in Gaza.

On the ground, Palestinian ambulances sped into Gaza neighbourhoods that have been too dangerous to enter for days.

Nine hours into the truce, they had found the bodies of more than 100 people in the debris, pushing the death toll to 1,000 Palestinians killed since the conflict erupted on July 8.

On the Israeli side, 37 soldiers have been killed, along with two Israeli civilians and a Thai worker.

Palestinians ventured onto Gaza's streets after the truce took effect, some eager to check homes they had fled, others to stock up on supplies while it was safe to do so.

In many places they found astonishing devastation: buildings levelled, entire blocks of homes completely wiped out by Israeli bombardment.

In northern Beit Hanun, even the hospital was badly damaged by shelling, and AFP correspondents came across the charred body of a paramedic as emergency workers searched for more dead.

There were similar scenes in Shejaiya, where stiff bodies lay on the floor of a room in one building, one caked in dried blood, all of them covered in dust.

'Humanitarian window'

To the east of southern Khan Yunis, residents hesitated to enter the Khuzaa neighbourhood, saying Israeli forces remained inside the border area.

And in nearby Bani Suheila, where 20 people were killed in a single Israeli air strike shortly before the truce began, women and children wept as they discovered their homes destroyed.

Hamas and Israel agreed to the "humanitarian window" early on Saturday morning, after Israel's security cabinet on Friday night rejected a US proposal for a seven-day truce during which the two sides would negotiate a longer-term deal.

Speaking after the rejection, at a news conference in Cairo with UN chief Ban Ki-moon, Kerry said Israel and Hamas "still have some terminology" to agree to on a ceasefire, but added they had "fundamental framework" on a truce.

But the two sides remain at odds over the shape of a final deal to end the fighting.

Hamas says any truce must include a guaranteed end to Israel's eight-year blockade of Gaza, while in Israel there are calls for any deal to include the demilitarisation of the Gaza Strip.

West Bank tensions

The situation in Gaza has created tensions in the West Bank, where protests against Israel's role in the conflict erupted after Friday prayers.

Troops shot dead two Palestinian teenagers early Saturday in separate clashes in the north and south of the West Bank.

That followed the deaths of six Palestinians on Friday -- five shot dead by Israeli troops and one killed by an Israeli settler.

International concern has mounted over the number of civilians killed in the Gaza conflict, including in a Thursday attack in which at least 15 people were killed in alleged Israeli shelling of a UN school.

The facility was sheltering some of the 100,000 Palestinians who have fled their homes during the fighting.

Rights groups say about 80 percent of the casualties so far have been civilians, and the UN agency for children UNICEF said on Friday that 192 children had been killed during the conflict.

The Israeli army on Saturday announced the death of two soldiers in Gaza fighting on Friday evening. It named one as Staff Sergeant Guy Boyland, 21, but did not give further details.

Three civilians have been killed inside Israel by rocket fire from Gaza, which continued on Saturday morning before the truce, with three shot down by anti-missile defences and one falling on open ground, the army said.

It said militants fired 60 rockets into southern Israel on Friday, with another 15 intercepted.