(CNN) -- Police were watching for any further violence Wednesday after a third night of rioting in Belfast, Northern Ireland, that left one officer hurt, officials said.
About 150 nationalist youths fired shots and threw petrol bombs and a pipe bomb at officers. They also shone high-powered laser pens into officers' eyes.
The Police Service of Northern Ireland said it was now investigating and hoping to identify those involved in Tuesday night's violence.
Burning barricades were set up in the Ardoyne area of the city, which has been a flashpoint of the recent violence. One vehicle was hijacked and set on fire, police said.
Police used water cannons to disperse the rioters and the violence was over by 2 a.m. (9 p.m. ET Tuesday), police said.
One officer was hurt, but not seriously, police said. Earlier there were reports that several had been injured.
Trouble also flared in other parts of Belfast.
The latest violence began after a decision to allow a Protestant parade to pass through a mainly Catholic neighborhood on July 12, a day when Protestants march to celebrate the victory of England's King William III over his ousted Catholic predecessor, James II, in 1689.
Known as The Twelfth, the holiday has previously been marred by violence and has been a source of tension between Catholics and Protestants for years.
Police had to remove demonstrators who staged a sit-down protest to block this year's march. Rioting erupted a short time later and more than 50 officers were hurt.
The previous night, 27 officers were hurt, including three who were shot at close range by a masked man armed with a shotgun.
Speaking at the House of Commons on Wednesday, British Prime Minister David Cameron condemned the "completely unacceptable behavior" of the protesters and praised the police as "brave" and "restrained."
"Over 80 police officers have been injured after being attacked, including by petrol bombs, pipe bombs, and bricks," Cameron said. "The police came under fire on Sunday night, and shots were again fired last night. The police have been forced to retaliate with baton rounds and with water cannons."
Cameron said Northern Ireland's police force is under local control, no longer governed by London, so "there is no excuse for anyone not to cooperate with that police force."
Journalist Peter Taggart in Belfast, Northern Ireland, contributed to this report.