York Regional Police say they're dismantling a drug lab found in a house near Bur Oak Avenue and Kennedy Road in Markham, north of Toronto.

Const. Andy Pattenden says officers went to the home Thursday to execute an unrelated search warrant in a theft investigation. When they arrived, officers discovered what they believed to be a clandestine drug lab.

Police called in its Drugs and Vice Unit to dismantle the lab.

A section of Holst Avenue between Brock Avenue and Harbord Street in Markham has been closed while police investigate. (Devin Heroux/CBC)

A section of Holst Avenue between Brock Avenue and Harbord Street in Markham has been closed in the meantime. Nearby homes have also been evacuated as a safety precaution.

Pattenden says it's too early to tell what kind of production they're dealing with, but says it's some kind of synthetic drug like methamphetamine or ketamine.

Police believe the operation was producing some kind of synthetic drug like methamphetamine or ketamine. (Devin Heroux/CBC)

He confirms police have made arrests in connection with the lab, but those details are only expected to be released tomorrow.

Police say clandestine drug labs can pose serious risks, including fires and explosions due to the dangerous nature of chemicals used in the production of illicit drugs.