Fraser Health is issuing an urgent warning about cocaine thought to be contaminated with a powerful opioid, possibly fentanyl.

According to the warning posted in a tweet from New Westminster police, first responders responded to at least 12 overdoses in Surrey on Sunday.

Drug users who do not feel well are urged to seek medical attention immediately.

If someone around you overdoses, call 911 and administer naloxone if it is available.

Fraser Health is also urging people to not use drugs alone and to use supervised sites.