Police and members of the Apprentice Boys Association came under attack by petrol bombers in a night of unrest in Londonderry.
Two petrol bombs were thrown at the Apprentice Boys Memorial Hall in the city centre from the direction of the republican Bogside area as people who had taken part in a parade earlier in the day socialised inside.
No-one was injured but police who attended the scene were then also subjected to attack, with a further 15 to 20 petrol bombs and other missiles thrown at them from nearby Fahan Street.
A number of wooden pallets were then placed on the street and set alight. No officers were injured and calm was restored at about 1am.
The violence unfolded amid raised tensions in the city after a number of contentious incidents during the Apprentice Boys annual August parade on Saturday.
Members of a loyalist flute band are to be reported to prosecutors after wearing a Parachute Regiment symbol on their uniforms during the parade.
Loyalists across Northern Ireland have been using the symbol to show support for Soldier F - the veteran facing prosecution for two murders and four attempted murders on Bloody Sunday in Derry in January 1972.
A large number of police officers accompanied the Clyde Valley Flute Band, from Larne, Co Antrim, as it made its way through the city.
A bus carrying the band home was then stopped by police on the outskirts of the city. Officers in armoured vehicles attended as the names of some bandsmen were taken.
Sinn Fein has also criticised DUP members, including East Londonderry MP Gregory Campbell, who posed for a photograph beneath a banner incorporating the Parachute Regiment insignia in the unionist Fountain estate.
Police are also investigating an illegal protest staged by dissident republican group Saoradh during the Apprentice Boys parade.
Five people were arrested on suspicion of public order offences during the day.
Commenting on Saturday night’s attacks, PSNI Superintendent Gordon McCalmont said: “Last night the Memorial Hall was busy with people socialising after the parade in the city and, while no-one was injured, this could have been much different had it not been for the actions of police.
“Police who deployed to the area to prevent further disorder were subsequently attacked by persons who threw 15 to 20 petrol bombs and other missiles in the area of Fahan Street. A number of pallets were also placed on the street and set on fire.
“Fortunately, no injuries were sustained by officers, but this violent behaviour cannot be tolerated.”
On the incidents during the parade, a PSNI spokesman said: “A report will be forwarded to the Public Prosecution Service in respect of behaviour and symbols displayed by one band.
“Police will also be reporting a number of individuals in relation to an un-notified protest.”
The spokesman said police would be working with the event organisers and the community to examine the issues emerging from the parade.