The PSNI are advising members of the public to avoid an area of Londonderry while they deal with what they described only as an “incident”.
There have been reports of “two loud bangs” from those living nearby.
An area in the Waterside has been cordoned off.
A police spokesperson said: “Police are currently in attendance at an incident in the Sevenoaks area of Derry/Londonderry.
“Cordons have been put in place whilst officers conduct their enquiries and members of the public are asked to avoid the area.”
The spokesperson added: “There are no further details at present.”
DUP Councillor David Ramsey said: “I have heard reports from people in that area that two loud bangs were heard, a short time apart.”
He added: “I would advise people to heed the advice of police and stay away from the area and allow them to carry out their work.”