A Republican parade due to take place later in County Tyrone will commemorate IRA members, including two killed by their own bomb.
The march through the village of Castlederg is restricted in places, but tensions are running high.
On Friday, 56 police officers were injured during loyalist violence in Belfast, and seven people have been arrested.
Pressure is mounting for a political solution to the violence which surrounds many parades.
The leader of the Progressive Unionist Party - Billy Hutchinson - says many people are feeling marginalised:
"No-one wants to see violence on the street," said Billy Hutchinson, leader of the Progressive Unionist Party.
"We've got to a stage now where working-class protestants, loyalists - whatever you want to describe them as - feel like white trash.
"I feel like they don't believe they live in a city of equals."