A "huge bang" was heard as police raided a block of flats in north Manchester.
Witnesses said they saw special forces swoop on the address in Northland Road, Blackley, on Wednesday evening.
Resident Chris Barlow said there was a "huge bang" and "huge police presence".
"There was about 30 people on the street - they said there's been an explosion at the flats, a bomb or explosion," he told the Press Association.
"There's CTU (counter terrorism unit) special forces - I spoke to one officer and they said they blew the door in and took a couple of people away."
Greater Manchester Police were unable to comment on whether the incident is linked to the investigation into the Manchester bombing on Monday, which left 22 dead and dozens injured.