Two people have been arrested after wads of cash were found on a rooftop in early morning raids.
Officers stormed homes in Heywood, Hollins and Blackley at around 6am this morning (Thursday).
Police discovered a 'significant amount' of cash had been stashed in bags and thrown onto the roof at the house in Blackley from the bathroom window.
GMP said it was thrown onto the roof in a 'last-ditch attempt to hide it from officers'.
Officers also seized a car and mobile phones.
© GMPTwo men were arrested after the cash was found in the raids
Two men - aged 29 and 37 - were arrested on suspicion of offences including conspiracy to supply drugs, money laundering and firearms offences.
They remain in custody for questioning.
The warrants were carried out by officers from GMP's City of Manchester Challenger Team, Xcalibre Task Force and the Tactical Aid Unit as part of Operation Foam.
The operation falls under the National Crime Agency-led Operation Venetic - an investigation into the criminal use of encrypted communication services.
Det Insp Ian McNabb of GMP's City of Manchester Division, said: "Today's result follows months of meticulous investigative work and is yet another successful step forward in our continued effort in disrupting this type of activity across Greater Manchester.
"Although we currently have two in custody for questioning, our investigation will continue and we would appeal to anyone who believes they hold information on suspicious activity - whatever that may be - to get in touch with police."
Anyone with information is asked to call police on 0161 856 0324; or Crimestoppers, anonymously, on 0800 555 111.