CAIRO - Officials of Egypt's Muslim Brotherhood said a gathering of its supporters near a mosque in a Cairo suburb was attacked early on Thursday after the Islamist movement's Mohamed Morsi was ousted by the army as head of state.

Independent confirmation was not immediately available.

Gehad El-Haddad, the movement's official spokesman, told Reuters he was among about 2,000 people still camping out at the site when, shortly after 3 am (0100 GMT), men in plain clothes began firing on the crowd, many of whom were praying. He said he saw several casualties being carried away.

He later tweeted that the attack lasted some 15 minutes.

Osama Gado, another Brotherhood official, also told Reuters by telephone from the site that men had thrown petrol bombs at the Morsi supporters and opened fire with shotguns and rifles. He said he was not sure if there had been casualties.

A wide area around the site has been cordoned off by the army since just before its announcement that Morsi had been removed and the constitution suspended. Troops have been letting demonstrators leave but not allowing people to enter the area.