The Palestinian decision-making body led by U.S.-backed President Mahmoud Abbas on Wednesday endorsed demands by Hamas for halting Gaza hostilities with Israel, a closing of ranks that may help Egyptian-mediated truce efforts.

With Israeli and U.S. encouragement, Egypt has tried to get both sides to hold fire and then negotiate terms for protracted calm in the Palestinian enclave where officials said 624 people, mostly civilians, have been killed in 15 days of fighting.

Hamas, the Gaza Strip's dominant Islamists, and other armed factions had balked at Cairo's offer, saying they wanted assurances of relief from an Israeli-Egyptian blockade and other concessions. The dispute was further complicated by distrust between Egypt under President Abdel Fattah el-Sisi and Hamas.

In a move that could effectively turn Abbas into the main interlocutor for a Gaza truce, his umbrella Palestine Liberation Organization (PLO) on Wednesday formally supported core conditions set by the Hamas-led fighters.

"The Gaza demands of stopping the aggression and lifting the blockade in all its forms are the demands of the entire Palestinian people and they represent the goal that the Palestinian leadership has dedicated all its power to achieve," senior PLO official Yasser Abed Rabbo said in Ramallah, the hub city in the Israeli-occupied West Bank where Abbas is based.

"We are confident Gaza will not be broken as long as our people are standing beside it to support it through all possible means until the invaders understand that our great people inside the homeland and outside will not leave Gaza alone." 

Gaza rocket lands near Israeli airport

Signalling that Abbas, too, sought a staggered cessation of hostilities, the Palestinian leader's Fatah faction on Tuesday proposed a truce followed by five days of negotiations on terms. 

There was no immediate response to the PLO statement from Hamas or Israel, which pressed the Gaza offensive it began on July 8 after a surge of cross-border rocket salvoes.

Earlier on Tuesday, a rocket fired from the Gaza Strip landed near Israel's main airport, wounding one Israeli and prompting all U.S. and some European and Canadian airlines to cancel flights to Tel Aviv, as the international community stepped up diplomatic efforts to revive a ceasefire proposal that was rejected by Hamas.

U.S. Secretary of State John Kerry and UN secretary-general Ban Ki-moon met with Egyptian and Israeli officials in a bid to broker a truce, while Israel's Transportation Ministry called on airline companies to reverse their decision, insisting the Ben-Gurion Airport is safe and completely guarded and saying there is no reason to "hand terror a prize," by halting the flights.

Palestinian militants have fired more than 2,000 rockets toward Israel, and several heading toward the area of Ben-Gurion Airport have been intercepted by Israel's Iron Dome defence system, but police spokeswoman Luba Samri said Tuesday's landing was the closet to the airport since fighting began two weeks ago.

The rocket heavily damaged a house and lightly injured one Israeli in Yehud, a Tel Aviv suburb near the airport, Samri said.

However, international airlines and passengers are growing more anxious about safety since last week, when a Malaysia Airlines jet was shot down over Ukraine, killing all 298 people on board.

Israel Palestine Gaza conflict

Palestinians take cover as warning Israeli airstrikes are fired at a nearby building in Gaza City on Tuesday. (Finbarr O'Reilly/Reuters)

The disruption to air travel, which includes Air Canada flights, came as Israel is increasingly suffering from the effects of the war in Gaza after nearly two weeks of largely remaining insulated as the air defence system dependably zapped incoming Hamas rockets from the skies and the military successfully repelled infiltration attempts on the ground and from the sea. That has changed since Israel launched a ground operation on Thursday.

Meanwhile, Israeli airstrikes continued to pummel a wide range of locations in Gaza and diplomatic efforts intensified to end the fighting that has killed at least 609 Palestinians and 29 Israelis — 27 soldiers and two civilians. The UN office of humanitarian affairs estimates that at least 75 percent of the Palestinian deaths were civilians, including dozens of children.

The fate of another Israeli soldier who went missing following a deadly battle in the Gaza Strip remained unknown, a defence official said Tuesday.

It was not immediately known if the missing soldier was alive or dead, the Israeli defence official told The Associated Press. The disappearance raised the possibility that he had been captured by Hamas — a nightmare scenario for Israel. In the past, Israel has paid a heavy price in lopsided prisoner swaps to retrieve captured soldiers or remains held by its enemies.

Military officials said the soldier, identified as Sgt. Oron Shaul, was among seven soldiers in a vehicle that was hit by an anti-tank missile in a battle in Gaza over the weekend. The other six have been confirmed as dead, but no remains have been identified as Shaul, the officials said. They spoke on condition of anonymity because they were not authorized to discuss the incident with media.

Hamas' claimed earlier this week that it had captured an Israeli soldier. Israel's UN ambassador initially denied the claim but the military neither confirmed nor denied it.

A representative of Shaul's family, Racheli Gazit, said that "so long as the verification has not been completed ... as far as the family is concerned Oron is not a fallen soldier."

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Palestinians evacuate a building after what witnesses said were warning Israeli airstrikes next to their homes in Gaza City July 22, 2014. (Finbarr O'Reilly/Reuters)

Abductions of Israeli soldiers have turned in the past into drawn-out mediation with opponents leading to prisoner releases. In 2008, Israel released five Lebanese militants in exchange for the remains of two soldiers killed in the 2006 Lebanon war.

Also in 2006, Hamas-allied militants seized an Israeli soldier in a cross-border raid and held him captive in Gaza until Israel traded more than 1,000 Palestinian prisoners for his return in 2011.

Hamas had threatened in the past to kidnap more Israelis and Israel says the militant group's attacks through tunnels that stretch into Israel are for this purpose.

Rockets reportedly found in Gaza school

Canadian Foreign Affairs Minister John Baird said Tuesday he wanted an investigation into reports that 20 rockets were found in a Gaza school operated by the United Nations Relief and Works Agency.

Baird is "calling for the UN to launch an immediate independent investigation to determine the facts surrounding these reports," after the UNRWA said it found the rockets at one of its schools during an inspection.

The agency runs more than 200 schools in Gaza, serving more than 230,000 students.

UNRWA said the vacant Gaza school is located near two buildings housing refugees who have fled. It was the second instance of militants accused of storing weaponry in a school during the latest offensive.

An UNRWA statement said staff were removed from the building where the rockets were found, adding that it "strongly and unequivocally condemns the group or groups responsible."

Rumours were circulating in Israeli media on Sunday that the rockets ended up in the hands of Hamas, but UNRWA denied the rockets were given to Hamas.

Hamas, with some support from Qatar and Turkey, wants guarantees on lifting the blockade before halting fire. The Islamic militant group has no faith in mediation by Egypt's rulers, who deposed a Hamas-friendly government in Cairo a year ago and tightened restrictions on Gaza — to the point of driving Hamas into its worst financial crisis since its founding in 1987.

The border blockade has set Gaza back years, wiping out tens of thousands of jobs through bans on most exports and on imports of vital construction materials Israel says could be diverted by Hamas for military use. Israel allows many consumer goods into Gaza, but experts say Gaza's economy cannot recover without a resumption of exports.

With files from CBC News