GAZA CITY (Ma'an) -- An Israeli airstrike damaged two media headquarters in Gaza City early Sunday, injuring at least six journalists, witnesses said.

Khader al-Zahhar, a cameraman with al-Quds TV, had a leg amputated due to injuries sustained in the attack.

The Al-Shawa building, struck in the early hours, houses a number of media organizations, including Ma'an News Agency's headquarters in the Gaza Strip.

A Ma'an correspondent said the impact was focused on the eleventh floor, where the office of al-Quds TV is located.

At least six journalists were moderately injured, five of whom were identified as Darwish Bulbul, Ibrahim Labed, Muhammad al-Akhras and Hazem al-Daour, all al-Quds TV employees.

An Israeli army spokesman said forces targeted the antennae of the building. He said it was used by Hamas for carrying out terror activities.

A second Israeli airstrike around 7 a.m. hit a second media complex in Gaza City , the al-Shuruq building.

Sky News Arabia and Al-Arabiya reported that their offices have been affected. There were no initial reports of injuries.

An Israeli army statement said both offices were targeted because they are part of "Hamas' operational communications." The military said "forces targeted roof communication devices to minimize damage."

PLO official Saeb Erekat strongly condemned the two strikes. "This attack on journalists and freedom of expression reflects Israel’s disdain for international law and the little value it affords the lives of Palestinians," he said in a statement.

"Last Thursday, the Israeli Government Spokesperson said that there is no free media in Gaza, which is an insult to the brave journalists covering the situation from there. It would now seem that some Israelis want to make sure that there is no free media in Gaza."

Hamas' Al-Qassam Brigades also blamed Israel for "trying to kill the power of word in Gaza," in a Twitter post.

Palestinian National Initiative leader Mustafa Barghouti said Israel was "trying to frighten the press and media so they won't report" and said targeting the press was a war crime.

"This is a intentional Israeli crime to silence the voice of Palestinian and international media in Gaza. Israel is trying to claim that there is no free media in Gaza. They are insulting the media," Barghouti told Ma'an.

Israel's army said later on Sunday it had "gained control of Hamas radio waves" broadcasting in the Gaza Strip.

A military spokeswoman refused to comment further on the purpose and content of the broadcasts, or its relation to the two earlier strikes on media headquarters in Gaza City.

Israeli news site Ynet reported that the army is using frequencies to send message's to Gaza's bombarded population, including asking citizens to stay away from targeted sites.