Three men are being held for allegedly stealing gold bullion from business premises in north London.
Scotland Yard said the robbery happened at a precious metal factory on the Brimsdown Estate in Enfield at about 2230 GMT on Saturday.
Flying Squad officers, who were acting on intelligence, stopped a suspect vehicle from driving away by shooting Hatton rounds at its tyres.
Two firearms and a quantity of gold bullion were recovered by police.
A number of staff were present during the robbery, but no-one was injured.
Two of the men, who were arrested for allegedly committing armed robbery, are being held at a south London police station.
A third man is being questioned at a police station in north London.