Four men have been arrested after a drug squad seized 17.6lb (8kg) of heroin worth £560,000.
Officers from the Scottish Crime and Drug Enforcement Agency (SCDEA) made the arrests in Glasgow's Balmore Road and recovered 11lb (5kg) of the drug.
A subsequent raid on an address in Maryhill found another 6.6lb (3kg) of the class A drug and 13.2lb (6kg) of cannabis resin with an estimated street value of £30,000.
Four men, aged 25, 30, 50 and 52, were arrested and charged with drug offences. One is from Glasgow and the others are from Burton- on-Trent in Staffordshire, Northampton and London.
Detective Chief Superintendent Athol Aitken, head of SCDEA investigations, said: "Thanks to our action, we have prevented these dangerous substances from reaching the streets of Scotland.
"Our operation yesterday would have been seen by members of the community who would not have been aware of what was actually happening before them. I would like to thank them for their support and understanding.
"Drug dealers have no regard for the harm they inflict on communities and are only interested in furthering their power and profit at the expense of vulnerable people.
"We are determined to seek out those responsible for this evil trade and ensure they are brought to justice regardless of where they reside."