Immigration enforcement officers carried out a series of raids in Perth city centre on Friday night.
It is understood businesses in County Place were among those being checked.
A Home Office spokeswoman declined to comment on the operation, saying only that it was “ongoing”.
It is understood the Home Office enforcement team were accompanied by police officers as they checked on the immigration status of employees.
The operation was the subject of online gossip, with one Twitter user writing: “Home Office immigration vans cruising the streets of Perth this evening. Not a sight you often see.”
One witness, who did not want to be named, saw the vehicles as they made their rounds.
He said: “I just saw two vans driving slowly round the inner ring road toward the top of the High Street at about 6.15pm. It looked odd as they were going very slowly.”
The Home Office immigration law enforcement organisation has replaced the UK Border Agency, which was previously responsible for seeking out