Petrol bombers attacked police after the annual Apprentice Boys parade in Derry today.
Devices were thrown in the city centre following the parade, which passed off without major incident.
Eight people have been arrested for public order offences, police said.
Earlier, up to 20,000 marchers and supporters, and more than 120 bands gathered in the city for the event.
Police chiefs paid tribute to the parade marshals and community representatives for helping to take any tensions out of the main event.
Chief Inspector Chris Yates, the Foyle area commander, also praised the community, and civic and business leaders for making positive contributions during weeks of planning before the event.
