Israel pounded Gaza with air strikes into the early hours of Sunday, destroying a tower block that housed news media organisations, while Palestinian militants fired rocket salvoes at Tel Aviv.
The hostilities showed no sign of letting up as they entered a seventh day, with Palestinians saying at least 145 people have been killed since the conflict began on Monday, including 41 children. Israel has reported 10 dead, including two children.
The 12-storey block in Gaza City brought down by Israeli air strikes housed the U.S. Associated Press and Qatar-based Al Jazeera media operations.
The Israel military said it was a legitimate military target, containing Hamas military offices, and that it had given warnings to civilians to get out of the building before the attack.
The strike was condemned by Al Jazeera and the AP, which asked the Israelis to put forward evidence.
"AP's bureau has been in this building for 15 years. We have had no indication Hamas was in the building or active in the building," the news organisation said. "We would never knowingly put our journalists at risk."
The United States told Israel "that ensuring the safety and security of journalists and independent media is a paramount responsibility," White House Press Secretary Jen Psaki said.
U.S. President Joe Biden later spoke to both Israeli Prime Minister Benjamin Netanyahu and Palestinian President Mahmoud Abbas in an effort to restore calm.
But both Israel and Hamas insisted they would pursue their campaigns, leaving no end to the hostilities in sight despite a U.N. Security Council meeting scheduled for Sunday to discuss the worse outbreak of Israel-Palestinian violence in years.
"The party that bears the guilt for this confrontation is not us, it's those attacking us," Netanyahu said in a televised speech.
"We are still in the midst of this operation, it is still not over and this operation will continue as long as necessary."
Netanyahu said Israel's air and artillery barrage had eliminated dozens of Hamas militants and taken out "hundreds" of the Islamist militant group's sites including missile launchers and a vast tunnel network.
AL-AQSA
Hamas began its rocket assault on Monday after weeks of 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, during the Muslim holy month of Ramadan.
Speaking to crowds of protesters in the Qatari capital of Doha, Hamas chief Ismail Haniyeh said on Saturday the fighting was primarily about Jerusalem.
"The Zionists thought ... they could demolish Al-Aqsa mosque. They thought they could displace our people in Sheikh Jarrah," said Haniyeh.
"I say to Netanyahu: do not play with fire," he continued, amid cheers from the crowd. "The title of this battle today, the title of the war, and the title of the intifada, is Jerusalem, Jerusalem, Jerusalem," using the Arabic word for 'uprising'.
Hamas, Islamic Jihad and other militant groups have fired around 2,300 rockets from Gaza since Monday, the Israeli military said on Saturday. It said about 1,000 were intercepted by missile defences and 380 fell into the Gaza Strip.
Israel has launched more than 1,000 air and artillery strikes into the densely populated coastal strip, saying they were aimed at Hamas and other militant targets.
The bombardments have sent columns of smoke above Gaza City and lit up the enclave's night sky.
Earlier this week the International Criminal Court's chief prosecutor, Fatou Bensouda, told Reuters the court was "monitoring very closely" the latest escalation of hostilities, amid an investigation now under way into alleged war crimes in earlier bouts of the conflict.
Netanyahu accused Hamas of "committing a double war crime" by targeting civilians, and using Palestinian civilians as "human shields."
The New York-based rights group Human Rights Watch said on Saturday it had "serious concerns that the attacks caused disproportionate destruction of civilian property" in Gaza.
FAILED DIPLOMACY
Biden's envoy, Hady Amr, arrived in Israel on Friday, before a meeting on Sunday of the U.N. Security Council.
But diplomacy has so far failed to quell the worst escalation in fighting between Israel and Palestinians since 2014.
The White House said Biden updated Netanyahu on "high-level" contacts with regional partners to restore calm, and raised concerns about the safety of journalists.
Biden also spoke with Abbas, for the first time since the U.S. leader took office in January.
But diplomatic efforts are complicated by the fact the United States and most western powers do not talk to Hamas, which they regard as a terrorist organisation. And Abbas, whose power base is in the occupied West Bank, exerts little influence over Hamas in Gaza.
In Israel, the conflict has been accompanied by violence among the country's mixed communities of Jews and Arabs. Synagogues have been attacked, Arab-owned shops vandalised and street fights have broken out. Israel's president has warned of civil war.
There has also been an upsurge in deadly clashes in the occupied West Bank.
An Israeli soldier shot at a Palestinian motorist who tried to run over soldiers at a military checkpoint late on Saturday, the military said. Palestinian health officials said the motorist had been killed. On Friday, 11 Palestinians were killed by Israeli troops, Palestinian medics said.
(Additional reporting by Dan Williams, Stephen Farrell and Ari Rabinovitch in Israel, Ali Sawafta in Ramallah, Aidan Lewis in Cairo, Nandita Bose in Washington; Writing by Rami Ayyub and Edmund Blair; Editing by Frances Kerry, Mark Potter and Daniel Wallis)
