It has been claimed members of the Orange Order breached a Parades Commission ruling during a protest at Drumcree in Portadown last night.
The Garvaghy Road Resident's Coalition said more than 30 Orangemen walked from Drumcree church to the edge of the nationalist Ballyoran estate before stopping to block traffic.
The Orange Order said it would not comment until it had 'all the facts'.
It has been banned from parading along the town's Garvaghy Road since 1998.
Sinn Féin Assembly member John O'Dowd said it was a deliberate attempt to raise tension in the area.
He said the Orange Order Grand Master Edward Stevenson should explain his organisation's conduct.
'Let us now hear from Mr Stevenson, let him finally emerge into the media and tell the people what is going on with the Orange Order under his leadership,' said Mr O'Dowd.
The PSNI said it had 'received reports from the community that there were possible breaches of the Parades Commission determination' and that they were investigating the circumstances.
