Shots were fired at police last night during disturbances on a loyalist estate in Bangor, Co Down.
The PSNI says it fired six impact rounds hitting six people during the trouble.
Tensions rose on the Kilcooley estate after police officers investigating serious crime carried out searches in the area.
A crowd, said to be up to 200-strong, threw petrol bombs and missiles following searches. Shots were fired at police officers at one stage.
No PSNI officers were injured but ten police vehicles were damaged and a number of cars in the area were set on fire.
A PSNI spokesperson described the outbreak as a sustained attack on police lines.
The Attenuating Energy Projectiles, or AEPs as they are called, used by police were described as a safer alternative to plastic bullets.
Calm was restored early this morning and the crowds dispersed.
PSNI investigations are continuing and no arrests have yet been made.
The North's Deputy First Minister Martin McGuinness said the Ulster Defence Association must shoulder the responsibility to de-escalate tensions within its community.
'I think it was utterly disgraceful and I think it has to be unreservedly condemned by everyone,' Mr McGuinness said.
He added that if people have complaints about the activities of the PSNI then they should make those complaints to the Police Ombudsman.
