US Secretary of State John Kerry has called on the Palestinian group, Hamas, to accept a ceasefire along the lines of an Egyptian proposal to end the raging Gaza conflict that has already killed at least 635 Palestinians and 31 Israelis.

The top US diplomat spoke in Cairo on Tuesday after meeting Egyptian President Abdel Fattah el-Sisi, whose government offered the ceasefire proposal last week.

The Palestinian leadership has proposed to Egypt a plan for a ceasefire to be followed by five days of negotiations to stop the fighting, Palestinian official Azzam al-Ahmed told reporters in Cairo on Tuesday.

Kerry's call comes as United Nations chief Ban Ki-moon met Israeli Prime Minister Benjamin Netanyahu in Tel Aviv to discuss how to stop the ongoing bloodshed and begin negotiating.

"My message is the same for Israelis and Palestinians: Stop fighting, start talking and take on the root causes of the conflict so that we are not at the same situation in the next six months or a year," he said.

In response, Netanyahu said: "We will do what we need to do to defend ourselves."

The Israeli prime minister said that the international community must hold Hamas accountable for consistently rejecting multiple ceasefire proposals.

Flights suspended

For Hamas, the root cause is the siege of Gaza, and it has consistently demanded that Israel and Egypt lift the blockade.



It also wants the release of dozens of prisoners who were freed in a 2011 swap for captured Israeli soldier Gilad Shalit but rearrested this summer.

"The conditions for a ceasefire are ... a full lifting of the blockade and then the release of those recently detained in the West Bank," its leader in Gaza, Ismail Haniya, said on television.

"We cannot go backwards, to a slow death," he said, referring to the Israeli blockade in force since 2006.

The flurry of diplomatic activities also comes as Israeli military reported that one of its soldiers is missing in Gaza and is presumed dead.

Meanwhile, several international airlines have suspending flights to Tel Aviv after a rocket attack near the airport.

The airlines were out ahead of aviation regulators in stopping service, with the US Federal Aviation Administration imposing a 24-hour ban on flights to Israel after US airlines acted.



Germany's Lufthansa, Italian airline Alitalia and Air France all acted before the European Aviation Safety Agency

issued an advisory.

Israeli airline El Al maintained its regular flight schedule.

UN school hit by shelling

The UN Security Council held an open debate on the situation in Gaza. The Palestinian ambassador called on the Security Council to stop what he called "Israel's slaughter of innocent people".

Several airlines suspend flights to Israel

The deadliest conflict in five years between Israel and the Palestinians has killed 635 Palestinians, many of them civilians, according to Gaza's health ministry. At least 31 Israelis, 29 of them soldiers, have died in the fighting.

According to the latest reports, a United Nations school sheltering displaced Palestinians in central Gaza has come under Israeli fire as a team was inspecting damage from a day earlier.

The official said a team, with Israeli clearance, was at the school run by the UN agency for Palestinian refugees, UNRWA, in al-Maghazi when Israeli tank shelling resumed, hitting the building, the AFP news agency reported.

Late on Tuesday, a series of Israeli air strikes across the Gaza Strip killed six people, medics said. More than 60 people have been killed in the past 24 hours.

Earlier in the day, Israeli aircraft and tanks hit more than 150 targets in the Palestinian enclave, including five mosques, a football stadium and the home of the late leader of Hamas' military wing, according to Palestinian police. At least seven Palestinians were reported killed in attacks.

Meanwhile, gunshots were fired on Tuesday into Al Jazeera’s bureau in Gaza City. Al Jazeera's Stefanie Dekker said two bullets hit the building. No casualties were reported.

Since the Israeli operation began on July 8, huge numbers of Palestinians have fled their homes, with the UN saying more than 100,000 people have sought shelter in 69 schools run by UNRWA.