U.S. Secretary of State John Kerry huddled Friday with U.N. chief Ban Ki-moon and Egypt's foreign minister as pressure built for a ceasefire in Gaza.

Kerry, who spent another night in Cairo reaching out by telephone to regional officials, met Ban and Egyptian Foreign Minister Sameh Shoukri for around half an hour.

Palestinian Islamist movement Hamas said Friday it fired three rockets at Tel Aviv airport, a day after U.S. and some European airlines had resumed flights after a two-day suspension.

"At 11:45 am (0845 GMT), the Qassam Brigades bombarded Ben Gurion airport with three M75 rockets," a statement from Hamas's armed wing said.

Iranians rallied nationwide on Friday in a show of support for Palestinians as arch-foe Israel pursued its deadly campaign against the Gaza Strip.

Demonstrations were held in Tehran and more than 700 towns and cities across the country on the last day of prayer and rest of the Muslim holy fasting month of Ramadan, state television reported.

Four hundred and eighty academics, lawyers, community activists and others criticized Canada's government for taking a decisively pro-Israel position amid the current conflict in the Gaza Strip, saying it "discredits Canada."

In an open letter published in the daily Globe and Mail, they said they "are profoundly perturbed by the unbalanced and partisan position adopted by the Canadian government and federal political parties regarding the current violence in Gaza."

Israeli security forces were on heightened alert Friday after a Palestinian man was shot dead during a huge protest in the West Bank against Israel's military offensive in Gaza.

Palestinian factions in the West Bank declared a "Day of Rage" after the Thursday night clashes, which took place around the West Bank and in some sectors of Israeli-annexed east Jerusalem.

Signs of renewed efforts for a Gaza ceasefire were evident on Friday as the death toll continued to climb after Israel shelled a U.N. shelter killing 15 Palestinians.

Israel's secretive security cabinet was expected to meet later in the day to discuss truce proposals passed to Israeli Prime Minister Benjamin Netanyahu by U.S. Secretary of State John Kerry earlier in the week, Israeli media said.

Fifteen people were killed Thursday when Israeli fire hit a U.N. shelter in Gaza, as the Palestinian toll in the 17-day conflict rose to 798, medics said.

Emergency services spokesman Ashraf al-Qudra said at least 15 people had been killed and 200 wounded by Israeli shelling of a school run by the U.N. agency for Palestinian refugees (UNRWA) in the northern town of Beit Hanun, where hundreds of civilians had sought refuge from the violence.

U.S. Secretary of State John Kerry worked the phones, including with Hamas allies, on Thursday, as he pressed efforts to end the bloodshed in Gaza, but aides warned gaps remained.

A day after he flew into Israel and cited signs of progress, Kerry was hunkered down in Egypt -- which drafted a proposal to halt the Israel-Hamas conflict -- and spoke to regional leaders by telephone.

Several hundred protesters demanded a halt to Israel's ground offensive in Gaza during a peaceful demonstration Thursday outside the Israeli embassy in Madrid.

About 400 demonstrators, many of them waving Palestinian flags in red, white, green and black, chanted "murderers" as police looked on.

Western nations are losing sympathy for Israel as casualties mount from its military operation in Gaza, Foreign Secretary Philip Hammond said on Thursday.

Speaking on his first official visit to the region since taking over as Britain's foreign affairs chief, Hammond insisted however that the cause of the crisis was Hamas militants firing rockets from Gaza into Israel.