Republican Garry Donnelly has gone on trial at the Magistrates Court in Londonderry charged with assaulting and obstructing police officers in the Water Street area of the city centre two years ago.
The 38-year-old, who is from Rinmore Drive, Creggan, also denies further charges of disorderly behaviour and of resisting arrest.
The offences are alleged to have taken place on November 16
2007. During the incident the defendant sustained a broken right arm.
Police witness Inspector John Neal told District Judge Barney McElholm that the incident took place after the defendant and two other men were placed under police observation outside the Foyle Street library.
The trial was adjourned until next week.