Two men remain in police custody in connection with the deaths of two Wigan drug users, who died from taking ecstasy from a potentially toxic batch.
Officers arrested the duo after Jordan Chambers, 19, died in Oldham and Gareth Ashton, 28, died in Wigan after taking the lethal pills.
The suspects, aged 33 and 34, have been arrested on suspicion of being concerned in supplying a controlled drug and remain in custody for police questioning.
Revellers and partygoers are being warned to be wary of the contaminated batch as up to ten people are thought to have been admitted to hospitals across Greater Manchester suffering from similar symptoms.
Detective Chief Inspector Howard Millington, from Wigan CID, said: “We are very concerned at how these deaths of two apparently fit young men have occurred.
“Our main concern is that there may be a contaminated quantity of illegal drugs and if this goes unchecked it could result in further deaths.
“If you are suffering adverse effects after taking one of these tablets I would advise you to go to hospital for a check-up.”
Officers are warning drug users against taking ecstasy tablets, heart-shaped in purple, green, yellow and blue.
The post mortems are scheduled to take place later this week.
Anyone with information should phone police on 0161 856 7149 or the independent charity Crimestoppers, anonymously, on 0800 555 111.