Officials of Egypt's Muslim Brotherhood said a gathering of its supporters near a mosque in Cairo suburb was fired on for several minutes early on Thursday, after Islamist President Mohamed Mursi was ousted by the army.
About an hour later, Reuter's correspondents found the site calm. Islamists have been gathered there for some days in a show of solidarity with Mursi as he came under pressure from the military.
Gehad El-Haddad, the movement's official spokesman, told Reuters by telephone he was among about 2,000 people still camping out when, shortly after 3 a.m. (0100 GMT), men in plainclothes 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 Mursi 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 Mursi had been removed and the constitution suspended. Troops have been letting demonstrators leave but not allowing people to enter the area.
Egypt Brotherhood says gathering fired on in Cairo