Soho Road in Handsworth was sealed off at around 9.30am on Wednesday morning as officers surrounded the Mobile Phone City shop.
Police responded to a call concerning the safety of a man in a flat on the road which connects the city to the M5 motorway.
A police negotiator was reportedly at the scene and four men were eventually arrested on suspicion of possessing a gun.
Nobody is believed to have been hurt but police were continuing to search the area on Wednesday afternoon.
A spokesman for West Midlands Police said: "This morning we have responded to a call concerning the safety of a man at a flat on Soho Road, Handsworth.
"Armed officers attended and we have arrested four men on suspicion of possession of a firearm.
"They are on their way into custody.
"We’ve not found anyone injured, or in need of our help yet.
"An investigation is underway and a search of the premises is being carried out.
"Anyone with any information should contact us via live chat on our website or call us on 101 quoting log number 901 of 22 December."