Two men have been arrested in Sheffield on suspicion of drugs and firearm offences.
Officers from the Yorkshire and the Humber Regional Organised Crime Unit, South Yorkshire Police and the National Crime Agency (NCA) led the early morning raids.
The raids came after six firearms including a sub-machine gun, ammunition and suspected class A drugs were seized on 6 April.
The arrest operation occurred in the Totley and Woodseats areas.
The weapons ammunition and suspected drugs were seized from an address on Abbeydale road in the city.
Enquiries are on going and the two men aged 29 and 22 remain in police custody.
South Yorkshire Police say that the operation was not terrorist related.