The Union flag is flying over Belfast's city hall to mark a royal birthday.
Loyalists are expected to demonstrate at the landmark as the flag is raised for the second time since city councillors voted to restrict the number of days it can fly to 18.
The flag was hoisted at dawn to mark the 48th birthday of the Earl of Wessex's wife Sophie.
Meanwhile police said two men arrested on Saturday during protests in east Belfast over the flag controversy will be brought before magistrates on Monday.
An 18-year-old was charged with disorderly behaviour and a 20-year-old with disorderly behaviour and provocative conduct. A teenage boy who was detained was released unconditionally.
Earlier, there had been a heavy police presence as hundreds of people attended a peaceful demonstration at the city hall.
Loyalist paramilitary chiefs in east Belfast, community leaders and clergy this week called for an end to the violence which has dogged parts of Northern Ireland since December 3.
More than 100 police officers have been injured since the disorder began.