Foyle Road in Derry has reopened after Army technical officers completed their examination of a suspicious object.
It was found last night during a planned operation against dissident republican activity. During the operation, a car was stopped close to the junction with Ferguson Street, and three men aged 54, 43, 23 were detained, along with a 16-year-old boy.
All four are being questioned at the PSNI's Serious Crime Suite in Antrim.
A suspected gun recovered from the vehicle has been taken away for forensic examination.
Derry City SDLP councillor John Boyle visited the scene this morning...