The Irish nationalist Sinn Fein party says two of its ministers in Northern Ireland's government were involved in a nighttime street clash in Belfast as they tried to block a moving police vehicle.

The Police Service of Northern Ireland says an independent ombudsman will investigate Friday night's violence in an Irish Catholic district called Peter's Hill.

It happened following an annual parade through north Belfast by Northern Ireland's major Protestant brotherhood, the Orange Order. Catholics clashed with police after failing to block a road beside Peter's Hill that formed part of the Orangemen's route.

Sinn Fein says Caral Ni Chuilin, Northern Ireland's arts minister, suffered ligament damage while trying to stop a police vehicle. Sinn Fein justice spokesman Gerry Kelly also clung to the police car but was not injured.