SPECIALIST drugs teams are currently scouring Hampshire woodland for drug-related evidence.
The search began last night and is continuing this morning.
But they confirmed they were not looking for any suspects or “human evidence” in the woods near Tunstall Road.
It prompted concern from local residents who said they saw officers running into the trees with torches and floodlights.
One resident, who asked not to be named, said: “A police van is blocking off the car park to a tower block and they have lit the woods up like a Christmas tree.
"I have seen a few police officers going into the woods but we have no idea what is going on.”
Another resident living opposite the woods told the Daily Echo the police operation began early last night, but that residents were in the dark about its purpose.
The woman, who asked not to be named, said: "I would say it was a shock to see so many police officers and vehicles, but unfortunately it's not that rare around here."
The Daily Echo asked Hampshire Police for further comment on the situation but none was received.
A Hampshire Constabulary spokesman said: "We can confirm a small area of woodland on Netley Common near Thornhill, Southampton is being searched by officers and staff from our dedicated 'Fortress' team.
"The search is a line of enquiry to locate potential evidence linked to illegal drugs and substance misuse across Hampshire.
"We would like to reassure local residents and visitors that there is no threat to their safety. This specific search is not looking for suspects or human evidence."
Operation Fortress is a Daily Echo-backed campaign attempting to crack down on drug-related violence in the city.
Anyone with information on the incident should contact police on 101 or call Crimestoppers anonymously on 0800 555 111.