Police have been pelted with bricks, bottles and pieces of masonry during disturbances close to a sectarian interface in Belfast.
Up to 60 youths were involved in the disorder, which broke out just after 7pm yesterday at Castlereagh Street in the east of the city.
Officers came under attack as they tried to move a crowd that had gathered close to the nationalist Short Strand.
Chief Inspector David Moore, area commander for east Belfast, said: " A range of missiles including bricks, blocks and bottles were thrown at the officers.
"One of the local neighbourhood sergeants was hit with masonry on the shoulder and injured.
"The windscreen of one of the police Land Rovers was also smashed."
Police have launched an investigation to identify those involved in the trouble.
Mr Moore added: " This behaviour is totally unacceptable and a police investigation has begun to identify youths involved."
Since April, there have been about 60 arrests for interface-related disorder in east Belfast.
DUP MLA Robin Newton described the violence as totally unacceptable.
He said: "There can be no justification for such an incident and it has resulted in a police officer being injured and the likelihood of young people coming before the courts and receiving criminal convictions.
"This type of behaviour sends out all the wrong messages from east Belfast when we are working to bring jobs and investment to the area.
"The PSNI need to the support of the entire community to help stamp out such incidents."