BOSTON (AP) — Boston's mayor is visiting supervised drug injection sites in Canada as Massachusetts policymakers weigh adopting one of the more controversial efforts to curb the national opioids epidemic.

Spokeswoman Ana Vivas says Mayor Marty Walsh is in Toronto on Thursday and then Montreal on Friday to tour a number of the facilities, which allow people to inject illegal drugs under the supervision of medical professionals.

Walsh has said he's interested in learning firsthand how the sites can direct more people into addiction treatment. The U.S. doesn't have any publicly sanctioned safe injection facilities, but Philadelphia, Seattle and San Francisco are among those actively considering them.

The Democratic mayor is traveling with other city advisers and also plans to meet with his counterpart mayors and other local public health and public safety officials.