Sixteen people have been arrested in an operation to disrupt "county lines" drug gangs across north Wales, Merseyside and Scotland.
Over 300 officers took part in dawn raids on 24 properties in Flintshire, Conwy, and Anglesey in north Wales, and in Liverpool and Scotland.
Police said they were targeting heroin and crack cocaine supplies.
Earlier this year, the National Crime Agency estimated 100 county lines drugs networks were operating in Wales.
"Distribution of controlled drugs will not be tolerated and we will continue to take positive robust action. However we can't tackle this alone and key to all our work is intelligence," said Supt Mark Pierce, from the north Wales force.
Officers confirmed there were four men and two women arrested in north Wales, seven men and two women in Merseyside, and one man in Dumfries, Scotland.
Police said those being held are being questioned over various suspected offences, including conspiracy to supply controlled drugs and money laundering.