Canadian police and health officials searched on Tuesday for a thief who made off with vials of HIV-contaminated blood plasma from a Vancouver hospital.

The thief pried open a locked freezer at a laboratory at St. Paul's Hospital during the weekend and removed the 19 vials that were marked with the lettering "HIV VL" and labeled with the patients' names, Reuters reported.

Police said they do not know what motivated the theft, but health officials said the risk to the public was minimal.

Akber Mithani, vice president of medical affairs at the hospital, which is home to an AIDS research program said, "The vials are sealed. Unless the blood is injected into someone's bloodstream, the public is not at risk."

If the vials were thawed, the virus would only survive for about 72 hours.