The emergency services are currently at the scene of a road traffic collision involving three vehicles.
The collision occurred outside St. Theresa's Chapel on Melmount Road in Sion Mills, Co. Tyrone.
The Melmount Road is on the main A5 route between Strabane and Omagh.
Traffic is moving slowly but there are delays.
"As soon as things are clear - we will be sure to let you know," said the PSNI.
"If possible, we advise that alternative routes be taken," added police.