Shots were fired during serious violence between nationalists and loyalists in the Short Strand area of east Belfast on Monday night. Police have blamed both sides for the trouble.
However, nationalist residents claimed they have been undergoing sustained attack from loyalists for a week. No one is reported to have been injured during the disturbances.
Petrol-bombs and other missiles were fired across the peaceline between the loyalist Cluan Place and nationalist Clandeboye Gardens. Chief Insp Mike Ellis of the Police Service of Northern Ireland said his officers witnessed shots being fried from the nationalist side.
"Police cannot confirm whether live rounds were used. That precipitated wide- scale violence along the Albertbridge Road," he said. A blast-bomb was also thrown into Cluan Place.
Mr Paul Hoey, a community worker, said a gunman appeared on a wall and fired six shots in the Protestant area. "After that, a barrage of bricks and bottles and anything else they could put their hands on came over into Cluan Place," he said.
"Around 300-400 nationalists threw everything they could get at the loyalist people."
But a nationalist resident of Clandeboye Drive, Ms Deborah Devenney, said her community came under attack first.
"There were eight petrol-bombs thrown," she said. "People's homes had been attacked all weekend."