It follows the report of a suspicious object this afternoon, Monday 9 September.
A Tesco store has been evacuated while the object is examined, and the road is currently closed at the junction with Davys Street and Irish Quarter West.
Inspector Rory Bradley said: “We’re grateful to the public for their patience while we carry out initial investigations.
“We are also appealing to anyone with any information to contact us on 101, quoting reference number 1485 of 09/09/19.”
Motorists are asked to seek alternative routes.
There are no further details at this stage.