Israel pummelled Gaza with air strikes and Palestinian militants launched rocket barrages at Tel Aviv and other cities on Saturday, with no sign yet of an end to the worst escalation in years in the region, almost a week into the conflict.
US and Arab diplomats are seeking to calm the situation. Violence overnight saw militants fire about 200 rockets at cities in Israel, whose planes struck what it said were targets used by Hamas, the Islamist group that runs Gaza.
At least 139 people, including 39 children, have been killed in Gaza since hostilities erupted on Monday, Palestinian medics said.
Israel has reported nine dead, including children.
The Israeli bombardment overnight killed more than 15 Palestinians in Gaza, medics said, including a woman and four of her children who died when their house in a refugee camp was hit. Five others died, with others wounded, the medics said.
Israel's military said about the incident that it had hit an apartment in the Beach refugee camp used by Hamas. It said details of the case were under review.
In Israel, thousands of Israelis ran for shelter. Sirens wailed repeatedly across Tel Aviv on Saturday. One rocket struck a residential building in the commercial hub's suburb of Ramat Gan, killing one person there, medics said.
In Gaza, Akram Farouq, 36, dashed out of his home with his family after a neighbour told him they had received a call from an Israeli officer warning that their building would be hit.
"We haven't slept all night because of the explosions, and now I am out in the street with my wife and children, who are weeping and trembling," he said.
Israel's military said its aircraft struck rocket launch sites and apartments belonging to Hamas militants.
In Israel's coastal city of Ashdod, Mark Reidman surveyed damage to his apartment building from a rocket hit.
"We want to live in peace and quiet," the 36-year-old said, adding he had to try to explain to his three young children "what happened, and why this is happening".
Hamas launched Monday's rocket assault after tensions over a court case to evict several Palestinian families in East Jerusalem and in retaliation for Israeli police clashes with Palestinians near the city's al-Aqsa Mosque, Islam's third holiest site.
Seeking A Ceasefire
Regional and international diplomatic efforts have yet to show any signs of halting hostilities. Egypt, which has been leading regional efforts, sent ambulances across its border with Gaza to bring Palestinian casualties to Egyptian hospitals.
US President Joe Biden's envoy Hady Amr, deputy assistant secretary for Israel and Palestinian affairs, arrived in Israel on Friday, before a meeting on Sunday of the UN Security Council. The US Embassy said in a statement that the envoy aimed "to reinforce the need to work toward a sustainable calm".
Hostilities between Israel and Gaza have been accompanied by violence in Israel's mixed communities of Jews and Arabs. Synagogues have been attacked, Arab-owned shops vandalised and street fights have broken out. Israel's president, who has a largely ceremonial role, has warned of civil war.
Palestinian casualties also extend beyond Gaza. Palestinians, who each year on May 15 mark their displacement in the 1948 war around Israel's creation, have reported 11 people killed this week in the occupied West Bank after protesters and Israeli forces clashed.
Egypt was pushing for a ceasefire so talks could start, two Egyptian security sources said on Friday. Cairo has been leaning on Hamas and pressing others, such as the United States, to secure an agreement with Israel.
"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," a Palestinian official said on Friday.
The United Arab Emirates called on Friday for a ceasefire and talks, offering condolences to all victims. In September, the UAE and Bahrain became the first Arab states in a quarter century to establish formal ties with Israel.
Living conditions in Gaza are worsening, with households now receiving just four hours a day of power instead of the usual 12, after lines from Israel and Gaza's sole power station were damaged, officials said. Fuel was also running low.
"The power plant may stop working completely on Sunday or Monday if fuel isn't allowed into Gaza," said Mohamed Thabet, spokesman for Gaza's power distribution company, which runs the network serving the enclave's 2 million people.
Israel's military said on Saturday about 2,300 rockets had been fired from Gaza at Israel since Monday, with about 1,000 intercepted by missile defences and 380 falling into the Gaza Strip.