Police in Belfast have come under gunfire for a third successive night, with Northern Ireland's political leaders condemning those behind the violence.

In Ardoyne, the scene of Monday night's major disturbances, a lone attacker armed with a handgun fired four to six shots as police clashed with masked men. No one was injured by the shots, which witnesses said appeared to have been aimed at a police surveillance camera recording the rioters.

Police officers in the nationalist area of north Belfast responded with water cannon as they came under fire from petrol bombs and at least one homemade grenade.

Northern Ireland's first minister, Peter Robinson, and the deputy first minister, Martin McGuinness, denounced the "thuggery and vandalism" of the rioters and defended their political efforts to ease tensions over controversial parades. Violence surrounding 12 July Orange Order marches left 82 officers injured.