Eleven people have been arrested on suspicion of conspiracy to supply class A drugs after raids across the North East.
More than 10 homes were searched as part of the probe, including addresses in South Hetton, Haswell, Ryhope, South Shields, Shildon, Hartlepool, Peterlee, Shotton Colliery and Bishop Auckland.
All those arrested were held for conspiracy to supply class A drugs.
They are currently being interviewed by detectives.
The action forms part of Operation Sledgehammer, which was launched in 2010 to combat organised crime in County Durham and Darlington.
Leading the investigation, Detective Inspector Graeme Pallas, said: “Today’s action is a result of a long running, ongoing police investigation which aims to tackle those suspected of being involved in drugs offences.
“We are determined to dismantle, disrupt and destroy the networks of those involved in drug dealing who blight our communities.”
The houses raided are in Pinedale Drive, South Hetton; Gloucester Terrace, Haswell; Blyton Avenue, Ryhope; Grays Walk, South Shields; Salters Lane, Shotton Colliery; Manor House Estate, Hutton Henry; Meryl Gardens, Hartlepool and an address in Haswell Plough.
Anyone with information about drug-dealing in their area can call the police on 101 or call Crimestoppers confidentially on 0800 555 111.