An Israeli air strike Saturday demolished the 13-floor building housing Qatar-based Al Jazeera television and American news agency The Associated Press in the Gaza Strip, AFP journalists said.
Israel "destroyed Jala Tower in the Gaza Strip, which contains the Al Jazeera and other international press offices," Al Jazeera said in a tweet, with an AP journalist saying the army had warned the tower's owner ahead of the strike.
Al Jazeera broadcast footage showing the building collapsing to the ground after the Israeli air strike, sending up a huge mushroom cloud of dust and debris.
Jawad Mehdi, the owner of the Jala Tower, said an Israeli intelligence officer warned him he had just one hour to ensure the evacuation of the building.
In a phone call with the officer, AFP heard him beg for an extra 10 minutes to allow journalists to retrieve their equipment before leaving.
"Give us ten extra minutes," he urged, but the officer on the other end of the line refused.
Wael al-Dahdouh, Al Jazeera's bureau chief in Gaza told AFP: "It's terrible, very sad, to target the Al Jazeera and other press bureaux".
Israel alleged its "fighter jets attacked a high-rise building which hosted military assets belonging to the military intelligence of the Hamas terror organisation".
"The building also hosted offices of civilian media outlets, which the Hamas terror group hides behind and uses as human shields," it said.
Israeli air and artillery strikes on Gaza since Monday have killed 139 people including 39 children, and wounded 1,000 more, health officials in the coastal enclave say.
'Shocked and horrified'
The Associated Press said it was "shocked and horrified" by the attack.
"This is an incredibly disturbing development. We narrowly avoided a terrible loss of life," AP President and CEO Gary Pruitt said in a statement about the attack on the building, which also housed Qatar-based Al Jazeera.
A dozen AP journalists and freelancers had been in the building but were able to evacuate, Pruitt said.
The White House, which has kept a relatively low profile on the Israeli-Palestinian flareup, said Saturday it has cautioned Israel about the importance of protecting independent media.
"We have communicated directly to the Israelis that ensuring the safety and security of journalists and independent media is a paramount responsibility," White House press secretary Jen Psaki tweeted.
Israeli defense officials said the building housed not only news bureaus but offices of Hamas militants.
AFP journalists watched the building collapse after the air strike, sending up a huge cloud of dust and debris.
Pruitt, in his statement, said, "The world will know less about what is happening in Gaza because of what happened today."
The New York-based Committee to Protect Journalists also demanded an explanation from the Israeli government.
"This latest attack on a building long known by Israel to house international media raises the specter that the Israel Defense Forces is deliberately targeting media facilities in order to disrupt coverage of the human suffering in Gaza," said CPJ Executive Director Joel Simon.
"We demand that the Israeli government provide a detailed and documented justification for this military attack on a civilian facility given the possible violation of international humanitarian law," Simon said.