Two crew members aboard HMCS Winnipeg, which is based in Esquimalt, B.C., have been charged in Japan with using a controlled substance, the Royal Canadian Navy said Tuesday in a statement.

The pair were detained Monday while the ship was in Tokyo for a port visit.

The navy said that originally three crew members were detained, including two members of the military and a civilian employee. One of the military crew has since been released, but the other two were charged.

"These allegations are obviously troubling," said Rear Admiral Gilles Couturier in a written release, which pointed out the navy has a zero-tolerance policy for illicit drug use. 

"All of our personnel, military and civilian, are expected to conduct themselves in a manner that brings credit to the navy, the Canadian Armed Forces, and our country as a whole."

No mention was made of the type of drugs involved. The navy says it's working with the Canadian Consulate and Japanese authorities.