Ten people have been arrested on suspicion of supplying class A drugs following a series of raids at homes in Wakefield, West Yorkshire.
Around 50 officers raided seven homes in the Lupset, Eastmoor and Belle Vue areas in the early hours of Monday.
Nine men and one woman were held on suspicion of supplying class A drugs, burglary and possession. They are being questioned by detectives.
Police said the raids followed several months of work gathering intelligence.
Ch Insp Mark Mulcahy, who led the operation, said: "Our aim is to disrupt the organised drugs market in the district by taking the supply off the streets and also using the Drug Interventions Programme to divert users into treatment.
"This operation should send a clear message out that drug dealing will not be tolerated and where members of the public provide us with information, we will take positive action."