The Police Service of Northern Ireland said 12 baton rounds were fired during violence in East Belfast last night sparked by a search operation.
At least four people were injured in the violence in the Mount Pottinger and Short Strand areas. Up to 500 people were involved in the disturbances.
Sinn Féin say the trouble erupted after a number of houses in the republican Short Strand district were raided.
Police said their officers and troops were pelted with petrol, acid and ammonia bombs. "Bricks, bottles and other missiles were also thrown," a police spokesman said.
Sinn Féin said at least four people, one of them a teenage girl, had been injured. One man was struck on the chest. There has been trouble in the area since the weekend when loyalist and nationalist crowds clashed.
Sinn Fein MLA Mr Alex Maskey said protests about the police and army action had been lodged with the two governments. "Houses were raided. People protested and one thing led to another. People are very, very angry," he said.