Attackers set fire to an Al Jazeera studio in Tahrir Square during rioting in central Cairo on Wednesday, the broadcaster said, dpa reported.
State-run newspaper Al Ahram quoted Manal Mahmoud, news director of Al Jazeera's Egypt Live channel, as saying that unknown men broke into the studio but were prevented from stealing its equipment when demonstrators intervened.
The attackers then set the studio ablaze, Mahmoud said, causing damage she estimated at 2 million Egyptian pounds (333,000 dollars).
The attack took place as clashes between protesters and riot police continued throughout Wednesday in the area.
The riots began on Monday evening when demonstrators marked the first anniversary of clashes that claimed the lives of at least 42 protesters last year.
The revolutionary April 6 Youth Movement said that one of its members was "clinically dead" on a life support machine in a Cairo hospital after the overnight clashes.
The health ministry put the total number of injured at 43 since Tuesday night but said that no deaths had been recorded.