Traffic delays between Bridgend and Derry following collision

There’s been a traffic collision in Derry close to the border at Bridgend, with traffic diversions in place. Motorists are experiencing delays as a result, and people are being advised to avoid the area.
The N13 is closed close to the Three Flowers Bar and Restaurant.

All traffic travelling to Derry from Bridgend is being diverted on to Whinhill Road (at 19^th Hole Pub) to Birdstown Junction, to Muff and on to Culmore.  Traffic coming from Derry is being advised to divert to Culmore and on to Muff.
There is significant traffic in the area at the moment, with the Foyle Cup and Foyle Maritime Festival underway.
Police are dealing with the incident, there are no details of injuries, if any.