Opponents of Egyptian President Mohamed Mursi clashed with supporters of the Muslim Brotherhood in Alexandria on Friday.
Demonstrators hurled stones and Molotov cocktails at each other near a train station, disrupting service.
Riot police were deployed to separate the two sides and prevent further confrontation.
Anti-Mursi demonstrators accused him and the Brotherhood of seeking to dominate the post-Mubarak era, while the Brotherhood accused the opposition of failing to respect democratic rules.