A studio used by the Al Jazeera TV network in Cairo was set on fire on Wednesday in an attack that an employee said was carried out by a mob that had been chanting slogans against the Qatari-owned station.

The studio overlooks Tahrir Square and is located near the scene of violent clashes between youths and the security forces this week in which dozens of people have been injured. Those confrontations grew out of protests to mark the first anniversary of lethal street battles in the same area.

The first-floor office used by Al Jazeera Mubasher Misr, a station set up after the uprising that toppled President Hosni Mubarak, was badly damaged by fire.