Yousef Al-Helou and Jabeen Bhatti

Special for USA TODAY

GAZA CITY - Britain's U.N. ambassador says there may be "an extremely short" humanitarian pause in the conflict in Gaza between Israel and Hamas on Saturday lasting several hours.

Mark Lyall Grant told reporters Friday that Britain is very disappointed at the failure to reach agreement on a sustainable cease-fire but perhaps a humanitarian pause "will open up a little bit of space to work on a more sustainable cease-fire."

U.S. officials later said Israeli Prime Minister Netanyahu had agreed to a 12-hour cease-fire in principle, but did not say if it came with a starting time. A Hamas spokesman, Sami Abu Zuhri, said the group agreed to a 12-hour lull, starting at 8 a.m. local time Saturday.

Lyall Grant said key foreign ministers will be meeting in Paris on Saturday "to decide precisely on the next steps."

Associated Press, Reuters, CNN and Yahoo! News reported that the cease-fire comes after Israel's Security Cabinet unanimously rejected a cease-fire proposal Friday that called for a week-long truce in the deadly conflict.

"Israel has agreed to a 12-hour ceasefire from 07:00 am Saturday," said a U.S. official traveling with Secretary of State John Kerry, according to Yahoo! News. Kerry was leaving Cairo without securing a longer cease-fire deal between Israel and Palestinian movement Hamas.

Kerry's proposal had called for a temporary pause in fighting to allow Israelis and Palestinians to broker a broader deal. Israeli TV reported the deal was rejected mainly because Israel would have to cut short its effort at destroying Hamas tunnels.

Meanwhile, Israeli Defense Minister Moshe Yaalon told troops Friday that Israel may significantly widen the Gaza ground operation.

Kerry said some "terminology" on the truce's framework still needed to be worked out, speaking at an evening press conference in Cairo where he met with U.N. Secretary-General Ban Ki-moon and Egyptian Foreign Minister Sameh Shukri.

"We don't yet have that final framework, but none of us are stopping," he said.

A deal proposed by Egypt last week was rejected by Hamas because the group said it wasn't consulted. Hamas says any peace deal must include the lifting of a blockade against Gaza.

The failure of the new cease-fire proposal comes as five Palestinians were shot and killed in protests Friday in the West Bank after Palestinians called for a "Day of Rage" against the Israeli military's operation.

The circumstances surrounding the shootings in the northern village of Hawara and the southern village of Beit Omar, near Hebron, were not immediately clear.

Security was beefed up Friday in Jerusalem and the West Bank after thousands clashed with Israeli security forces Thursday night, leaving at least one Palestinian dead. Thursday's protests at a West Bank checkpoint and in East Jerusalem marked the largest demonstrations in those areas in several years.

The violence follows the shelling Thursday of a U.N. school, where at least 15 were killed and dozens wounded as the U.N. was trying to evacuate civilians in the northern town of Beit Hanoun.

The Palestinian Red Crescent said Israeli shells hit the school. The Israeli military said it was reviewing the incident and suggested Hamas-launched rockets may have been responsible for the deaths.

The conflict — in its 18th day — has killed 828 Palestinians and left 5,200 injured, said Ashraf al-Kidra, a Palestinian health official. In Israel, 38 people have been killed since July 8, including 35 soldiers, two Israeli civilians and a Thai worker.

The Israeli military said Friday that Oron Shaul, an Israeli soldier Hamas claimed to be holding, was in fact killed in battle Sunday.

In Tel Aviv, an Air Canada flight from Toronto aborted its first landing attempt Friday after Hamas fired several rockets toward Ben Gurion International Airport. But the Boeing 767-300 landed safely 10 minutes after the go-around and the airline plans to continue flying to Israel.

Five miles before landing, flight AC84 was advised by local air-traffic controllers to perform a standard go-around "until airspace conditions could be confirmed as safe for landing," said Isabelle Arthur, an airline spokeswoman. The plane landed safely at 12:07 p.m. and return flight 85 departed for Toronto at 1:59 p.m., Arthur said.

"We plan to operate this evening's flight to (Tel Aviv) as scheduled," Arthur said.

Meanwhile, Palestinian Justice Minister Saleem Al-Saqqa and Ismail Jabr, the Gaza court public prosecutor, filed a complaint to the International Criminal Court on Friday, accusing Israel of war crimes, including apartheid, attacks against civilians, excessive loss of human life and colonization.

Support for Hamas, in spite of the casualties — or some say because of them — is growing in Gaza.Early Friday, Israeli planes hit 30 houses throughout Gaza, including the home of Salah Hassanein, a leader of the military wing of Islamic Jihad, the second-largest militant group in Gaza after Hamas. Hassanein and two of his sons were killed in the strike, said Gaza police spokesman Ayman Batniji and al-Kidra. The Israeli army confirmed the strike.

"The problem is not with Hamas, the problem is the occupation," said Arafat Yasin, 46, a displaced resident from the Shijaeyyah neighborhood in east Gaza City that came under heavy bombardment last weekend. "The Palestinian Authority has been engaged in peace talks with Israelis for over 20 years, and the actions of the Israelis reflect their unwillingness to end their occupation."

"It's clear that they – the Israelis — are not interested in peace," he said.

Bhatti reported from Berlin. Contributing: Bart Jansen in Washington; The Associated Press