The worst violence between Israelis and Palestinians in seven years intensified on Saturday, as an Israeli airstrike destroyed a prominent high-rise building in Gaza City that housed media outlets including The Associated Press and Al Jazeera.
The Israel Defense Forces said its fighter jets struck the media tower because it also contained military assets belonging to Hamas. The I.D.F. said it had provided advance warning to civilians in the building to allow evacuation.
Gary Pruitt, chief executive of the A.P., said he was “shocked and horrified” by the destruction of the building. The news agency was seeking information from the Israeli government, he said on Twitter.
The Biden administration has “communicated directly to the Israelis that ensuring the safety and security of journalists and independent media is a paramount responsibility,” Jen Psaki, the White House press secretary, said on Twitter.
The attack followed an Israeli airstrike overnight that killed at least 10 members of an extended family in a refugee camp in Gaza, after which Hamas militants aimed another round of rockets at Tel Aviv.
The attacks occurred after a senior American envoy, Hady Amr, arrived in Jerusalem to help broker a cease-fire. Mr. Amr, the United States deputy assistant secretary of state for Israel and Palestinian affairs, was scheduled to meet with senior Israeli and Palestinian officials in Jerusalem and the West Bank.
But while Hamas and Israeli officials signaled late Friday that they were open to discussing a cease-fire, fighting continued unabated for much of Saturday, even as American, Egyptian and Qatari attempted to negotiate a pause in fighting.
At least 12 people were killed overnight in Gaza, Palestinian medics said on Saturday morning. And for the fifth consecutive day on Friday, Hamas rockets had targeted Israeli towns.
The Israeli military said it had killed dozens of high-ranking Hamas commanders and damaged the militant group’s network of tunnels beneath Gaza, significantly weakening Hamas.
It was not clear whether such losses were the reason a Hamas spokesman, Fawzi Barhoum, told Al Jazeera in a Friday night interview that the group would decide whether to negotiate a “calming” in the fighting under certain conditions. Israel, Mr. Barhoum said, must meet unspecified demands about “lifting its hand” from Gaza and the sites of clashes in Jerusalem, including the Aqsa Mosque.
Israeli security officials said they would be open to cease-fire talks, according to the Israeli news media.
The health ministry in Gaza that said at least 139 people had died in Israeli airstrikes and shelling, 39 of them children, with about 1,000 injured. Those numbers could not be independently verified. The United Nations said 10,000 Gazans had left their homes to take shelter in schools, mosques and other places. In Israel, the hostilities have left seven civilians, including a 5-year-old boy, and one soldier dead.
Power in Gaza was down to five hours a day in some places, and water came out of the pipes only once every few days. Any efforts to contain what had been a worsening coronavirus infection crisis all but ceased.
In Israel, the always-fraught notion of coexistence between Arabs and Jews seemed to be cracking amid the burning apartments and synagogues, the thrown stones and homemade bombs.