Police and fire crews were pelted with bricks and fireworks during unrest in Derry City last night.
Up to 50 youths turned on the authorities as they dealt with a car set alight in the city's Shantallow district.
Officers moved in last night after being alerted to a so-called scrapper vehicle being driven in the area.
They stopped the car only for it to be set on fire by the crowd at Ardnamoyle Park.
Fire and Rescue Service teams called in were attacked with fireworks, police said.
The devices were also thrown at police, along with stones and poles.
No one was injured but windows and wing mirrors on a police car were damaged.
Inspector Paul Stevenson hit out at those who targeted his officers and firefighters.
He said: "Attacks on the emergency services such as this present a very real risk of tying up resources which could be better used in an emergency scene."
PA