Israel pummeled Gaza with artillery fire and air strikes on Friday as it targeted Palestinian militant tunnels to try to stop persistent rocket attacks on Israeli towns.
In a 40-minute, pre-dawn offensive, at least 13 Palestinians were killed, including a mother and her three children whose bodies were pulled from the rubble of their home, health officials in Gaza said.
The Israeli operation included 160 aircraft as well as tanks and artillery firing from outside the Gaza Strip, Israeli military spokesman Lieutenant Colonel Jonathan Conricus said.
Palestinian rocket barrages against southern Israel swiftly followed on the fifth day of the most serious fighting between Israel and Gaza militants since 2014.
An Israeli military official later said more than 2,000 rockets had been fired from Gaza into Israel since the start of the conflict and that Israel had destroyed several km (miles) of tunnels used by the militants.
Egypt was leading international efforts to secure a ceasefire and ensure the conflict does not spread. Security sources said neither side appeared amenable so far but a Palestinian official said negotiations intensified on Friday.
UN Secretary-General Antonio Guterres appealed for an immediate ceasefire.
"Fighting has the potential to unleash an uncontainable security and humanitarian crisis and to further foster extremism...," UN spokesperson Stephane Dujarric said.
French President Emmanuel Macron also urged a return to peace during a telephone conversation on Friday with Israeli Prime Minister Benjamin Netanyahu.
Hamas, the group that rules Gaza, launched the rocket attacks on Monday, in retaliation for Israeli police clashes with Palestinians near al-Aqsa Mosque, Islam's third holiest site, in East Jerusalem.
Violence has since spread to cities where Jews and Israel's minority Arab community live side by side. There have also been clashes between Palestinian protesters and Israeli security forces in the Israeli-occupied West Bank, where health officials said 10 Palestinians were killed on Friday.
System of tunnels
The Israeli military has put the number of militants killed so far in the Israeli attacks at between 80 and 90.
At least 119 people have been killed since Monday in Gaza, including 31 children and 21 women, and 900 others wounded, Palestinian medical officials said.
Among eight dead in Israel were a soldier patrolling the Gaza border and six Israeli civilians, including two children, Israeli authorities said.
The UN Office for the Coordination of Humanitarian Affairs said there were reports of more than 200 housing units destroyed or severely damaged in Gaza and hundreds of people seeking shelter in schools in the north of the coastal enclave.
Israel says it makes every effort to preserve civilian life, including warning in advance of attacks.
"What we were targeting is an elaborate system of tunnels that spans underneath Gaza, mostly in the north but not limited to, and is a network that the operatives of Hamas use in order to move, in order to hide, for cover," Conricus told foreign reporters, adding that the network was known as "the Metro".
Israeli warplanes bombed the houses of three senior Hamas military commanders in central Gaza on Friday that had already been evacuated, local residents said.
Israeli planes bombed and destroyed the headquarters of the Hamas-run interior ministry in west Gaza City, the ministry spokesman said late on Friday.
Dozens of mourners took part in the funeral of six people - members of two families whose houses were hit by Israeli air strikes on Thursday - in the southern Gaza town of Rafah.
Holding the cloth-bound body of his 19-month-old nephew in his arms, Khamees al-Rantissi said their house was bombed without prior warning. "What was this child doing? What threat did he pose for the state of Israel?" Rantissi asked.
Netanyahu said on Thursday the campaign "will take more time". Israeli officials said Hamas must be dealt a strong deterring blow before any ceasefire.
The Israeli military's build-up of forces on the Gaza border has raised speculation about a possible repeat of ground invasions during Israel-Gaza wars in 2014 and 2009, but Israel is loath to risk a sharp increase in military casualties.
Flurry of diplomacy
Egypt was pushing for both sides to cease fire from midnight on Friday pending further negotiations, two Egyptian security sources said, with Cairo leaning on Hamas and others, including the United States, trying to reach an agreement with Israel.
"The talks have taken a real and serious path on Friday," a Palestinian official said. "The mediators from Egypt, Qatar and the United Nations are stepping up their contacts with all sides in a bid to restore calm, but a deal hasn't yet been reached."
The foreign ministers of Egypt and Jordan discussed on Friday efforts to end the Gaza confrontation and to prevent "provocations" in Jerusalem, Egypt's foreign ministry said.
The hostilities have fueled tension between Israeli Jews and the country's 21% Arab minority. Violence continued in mixed communities overnight after street fighting and tit-for-tat attacks that prompted Israel's president to warn of civil war.
Pro-Palestinian protests were planned in many Arab towns and villages in Israel on Friday night, including Nazareth.
Sheikh Ikrima Sabri, who led Friday prayers at al-Aqsa Mosque, decried the treatment of the mosque by Israeli forces.
He said its "sanctity has been violated several times during the holy month of Ramadan" in what he called violations "unprecedented" since the 1967 Arab-Israeli war.
Major airlines have suspended flights to Israel and at least two owners of tankers delivering crude oil asked to divert from Ashkelon to the port of Haifa, farther north of Gaza, because of the conflict, shipping sources said on Friday.
There were pro-Palestinian protests in Jordan, Bangladesh and elsewhere, but the broader picture across the Islamic world, where Muslims are marking the Eid al-Fitr holiday and where restrictions on movement due to COVID-19 are in place in some countries, was noticeably muted.
The UN Security Council will publicly discuss the worsening violence on Sunday, diplomats said.
