Police attended a “pre-planned” operation on Friday morning in the West End of Dundee.
A police presence is visible near the junction of Abbotsford Place and Peddie Street.
There is no wider risk to the public, a spokesman for the force said.
There were 10 police vehicles at the height of the swoop, included armed police and officers accompanied by dogs.
Callum Jones, who lives on Abbotsford Place, said: “I saw armed police, with MP5s and pistols on their waists.
“They stayed for about an hour, showed up at 9:30am.
“I was scared because I was playing some video game with a police alert in it and suddenly I saw them out my window.
“It seems like this was pre-planned because they’ve been patrolling up the street for a while.”
One resident, who asked not to be named, said: “I saw two police cars and a van coming round at about 9.25, but I didn’t think much of it and just got back to my university work.
“We do get the occasional police car, usually just a single one, so this is a lot more than normal.”
Other residents have also reported sightings of armed officers, with one saying: “The police breached the door open at one of the flats.
“Both ends of the street had been blocked off and we were told to stay in our houses.
“The police in the close were in full tactics gear, they were in full black, combat, tactical gear with rifles and handguns.”
A police spokesman said: “Officers executed a warrant at an address on Abbotsford Place in Dundee during the morning of Friday March 26 during a pre-planned operation as part of an ongoing investigation.
“Enquiries are ongoing and there is no risk to the wider public.”