Israel alleged Tuesday that a Gaza media building it destroyed was used by Hamas to jam air defenses as it offered to help the Associated Press rebuild its bureau.

Israel's ambassador to the United States, Gilad Erdan, gave the most detailed explanation yet of the decision to strike the tower as he met the head of the news agency, Gary Pruitt, at its New York headquarters.

"The unit was developing an electronic jamming system to be used against the Iron Dome defense system," Erdan said, referring to the anti-missile shield that intercepts Hamas rockets.

He praised the role of the Associated Press, one of the world's major news agencies along with Agence France-Presse and Reuters, and said he did not imagine AP employees were aware of the alleged use of the building by Hamas.

"Israel did everything it could to make sure that no employees or civilians were hurt during this important operation," he said in a statement released a day after his meeting with AP executives.

"In contrast, Hamas is a genocidal terrorist organization that has no regard for the press. It purposely places its terror machine in civilian areas, including in offices being used by international media outlets," he said.

Erdan said that Israel is "willing to assist" the Associated Press in rebuilding its office in Gaza, which is controled by Hamas, a militant Islamist group.

The AP and international media rights groups earlier called for an independent investigation into allegations that the Jala Tower building was used by Hamas.

The air strike also destroyed the office of Al Jazeera, the Qatar-based television network that has frequently irritated both Israel and Arab states with its coverage.

The owner of the Jala Tower had unsuccessfully pleaded for 10 extra minutes to let Al Jazeera retrieve its equipment but an Israeli officer rejected the request and went ahead with the strike.

The attack came during a May 10-21 military escalation, with Hamas firing rockets into Israel in response to what it considered provocations in Jerusalem against the Palestinian population.

Israeli strikes killed 260 Palestinians, including 66 children adn some fighters, and wounded more than 1,900 people, the Gaza health ministry says.

Rockets and other fire from Gaza killed 13 people in Israel, including a child and an Arab-Israeli teenager and an Israeli soldier, medics and the military say. Some 357 people in Israel were wounded.