Israeli warplanes destroyed a tower in Gaza hosting international media on Saturday, the Associated Press said.
Al Galaa Tower also housed Al Jazeera news channel.
Reports said journalists in the tower, which also had commercial offices, were given one hour to evacuate the building in advance of the bombing.
The Israeli military has in many cases called owners of large tower blocks in Gaza, giving them notice that their building will be destroyed in an air strike.
Al Jazeera English producer Linah Alsaafin tweeted that her colleagues were not allowed to remove their equipment from the building before it was destroyed.
"The owner of the building is telling the Israelis to give the media time to evacuate their equipment from the building. The officer said no," she said.
Video footage from near the office block showed it crumbling to the ground following a large explosion.
Later in the afternoon, the Israeli military issued a statement on the destruction of the building, saying it "contained military assets belonging to Hamas military intelligence", and that civilians had been given time to evacuate.
Writing for AP about the building earlier on Saturday, journalist Fares Akram said that he felt safe in his office at Al Galaa, believing that the Israelis would not target foreign media.
"The Associated Press office is the only place in Gaza city I feel somewhat safe. The Israeli military has the co-ordinates of the high-rise, so it's less likely a bomb will bring it crashing down," he said.
Later on Saturday, White House press secretary Jen Psaki issued a statement on the attack.
"We have communicated directly to the Israelis that ensuring the safety and security of journalists and independent media is a paramount responsibility," she said.