Two men were arrested at their Cocorite apartment on Tuesday, after police executed a warrant and found a high-powered rifle in the living room.
Acting on information, officers from the Western Division Task Force conducted the anti-crime exercise between 2 pm and 6 pm at Phase 1, Powder Magazine, Cocorite.
At 2.30 pm, officers went to Building E and entered the apartment of a 22-year-old man, where they began searching for arms and ammunition.
Lawmen later found the machine gun and holster hidden inside a three-seater couch in the living room.
The two male occupants, including the owner of the apartment, along with another tenant from Building C, were both arrested in connection with the find.
The officers later went to the home of a priority offender at Ross Lands, St James, where they executed a warrant for firearms and ammunition but nothing illegal was found.
The exercises were sanctioned by Snr Supt Henry and coordinated by Supt Williams and Insp Grant and included Sgt Dominique.
PC Mc Clean is continuing enquiries.