CAIRO (Reuters) - Three hours of street fighting in central Cairo on Friday evening between hundreds of supporters and opponents of ousted President Mohamed Mursi eased after the army deployed units in armored vehicles.

In early evening, a group of Islamist supporters of Mursi gathered near the national broadcasting headquarters on the banks of the Nile, about a kilometer (half a mile) from Tahrir Square, where Mursi's liberal opponents have set up camp.

The army deployed some troops and vehicles to keep rival sides apart but intermittently running battles took place around and across the Sixth October Bridge across the Nile.

Reuters journalists heard gunfire on several occasions. State television pictures showed people throwing or shooting fireworks at rival protesters. They also threw rocks.

Small groups huddled behind makeshift shields, using these as positions from which to attack.

After some three hours, half a dozen armored personnel carriers drove across the bridge at speed at then took up position. Calm returned, bystanders gathered around the military vehicles, chatting to the soldiers. Traffic resumed.

Brotherhood spokesman Gehad El-Haddad said a group of Mursi supporters had been attacked near the state television building and had later withdrawn back across the river. He said at least 18 of them had been wounded.

The health ministry, as reported by state television, recorded 17 deaths in violence nationwide.

(Reporting by Patrick Werr, Paul Taylor, Amr Abdallah Dalsh and Alastair Macdonald; Editing by Alexander Dziadosz)