Seven people have been arrested on suspicion of weapons and drug offences following armed raids at locations including Suffolk.
Operations took place on Monday in Aylesbury, Thetford and Newmarket.
Detectives from the Met's specialist crime unit carried out the joint operation with Thames Valley Police and Norfolk Constabulary.
Six firearms, ammunition and suspected class A drugs were recovered, and two people were arrested, after a vehicle was stopped by armed officers in Newmarket, the Met reported.
Three people were arrested on suspicion of conspiring to import firearms following a search of premises in Aylesbury.
A man was arrested after armed officers from Norfolk Constabulary stopped a vehicle in Thetford and found £9,000 cash.
A woman was arrested after a subsequent search of a house in Aylesbury resulted in the discovery of a handgun.
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