Eighteen people are being questioned following morning raids in an operation tackling drugs in Shropshire.
More than 200 police officers were involved and warrants were executed at 18 addresses in Telford and two in Wolverhampton in the West Midlands.
Fourteen men and four women have been arrested, including two men and a woman held in Wolverhampton.
Police said the main addresses they were searching in Telford were in Wellington, Hadley and Leegomery.
Other addresses were being searched in Wolverhampton.
Warrants were executed just before 07:30 BST and those in custody have been arrested on suspicion of a variety of drugs offences, including conspiracy to supply controlled drugs, police said.