Violence has broken out in north Belfast, capital of Northern Ireland, on Monday in opposition to the march of the Protestant Orange Order, Britain's Sky news reported.

Six officers were injured in Belfast during the violence, police said.

The parade by the Orange Order commemorates the Battle of the Boyne in 1690 which saw Prince William of Orange defeat the Catholic forces of King James. Riot police are tackling protesters who have hurled petrol bombs, fireworks and rocks.

In a separate incident in the northwestern city of Londonderry, another police officer was injured, and in County Antrim, three officers have been hurt after petrol bombs and other missiles were thrown. It is reported that up to 500,000 people are expected to take to the streets of Northern Ireland on Monday as the Orange Order marching season reaches its climax.

(Xinhua News Agency July 14, 2009)