Fifty-seven RUC officers were injured in rioting following an Orange parade near the Garvaghy Road in Portadown, Co Armagh last night, a spokeswoman for the force said.
The RUC previously said 20 officers were hurt but revised the figures upwards this morning.
Assistant chief constable Mr Stephen White condemned rioters who threw acid, petrol bombs, paving slabs and fireworks during two hours of disturbances. Catapults were used to pelt missiles at police and troops and there was even hand-to-hand fighting between trouble-makers and security forces, he said.
Nationalists accused the RUC of being "heavy handed" and said at least a dozen plastic bullets were fired. They claim the fighting was provoked by loyalists breaking parade restrictions.
Speaking this morning the Sinn Féin president Mr Gerry Adams called into question the use of plastic bullets against nationalists when no such action was taken in more serious disturbances in riots near Manchester last night.
He said he had raised the issue with both governments.
Mr Adams said: "Plastic bullets are lethal, deadly weapons and they should be withdrawn from use immediately.
"The speed with which the RUC is prepared to use them reinforces the need to replace that paramilitary force with a genuine new beginning to policing."
Sinn Féin Assembly Member Mr Dara O'Hagan criticised the Parades Commission for ignoring its appeals to halt the Parkmore Junior Orange march further away from the overwhelmingly Catholic Garvaghy Road.
Mrs Brid Rodgers, SDLP Assembly for Upper Bann which includes Portadown and a minister in the Northern Ireland Executive, said she was raising the subject with the Government.
Yesterday's march was heavily policed, with military back-up and a large metal barrier placed across the road. Mr White said it passed off without incident but that groups of men and youths confronted officers on public order duty as they were withdrawing.
He said: "I strongly condemn those people who were involved in a vicious, violent attack on my officers who were enforcing the Parades Commission decision in respect of junior Orange Order marches in Portadown.
The annual march passes the bottom of the road - as opposed to the top where Orangemen at Drumcree Parish Church have been banned from marching since 1998.
additional reporting PA
