A 39-year-old Portland man pleaded guilty on Wednesday in federal court to robbing a Portland pharmacy and prompting city police to close Congress Street for several hours.

U.S. Attorney Thomas E. Delahanty II said Jason Campbell pleaded guilty in U.S. District Court before Judge Jon D. Levy to robbing the CVS pharmacy at 510 Congress St. on April 11.

According to court records and evidence presented at the plea hearing, Campbell entered the pharmacy carrying a backpack. As he approached the pharmacy counter, Campbell opened the backpack, told the pharmacist he had a bomb, and displayed what appeared to be a soda bottle with wires attached to it.

Campbell then told the pharmacist to evacuate the store and close the gate at the front of the store. He demanded that the pharmacist give him opioid pain medications. Once he had the drugs, Campbell ran off, disposing of his outer clothing and backpack in a nearby trash can.

The Portland Police Department’s bomb squad closed Congress Street, between Brown and Casco streets, for 3½ hours after they found his backpack. The device was a backpack with a cellphone attached by wires and what appeared to be a plastic soda bottle containing liquid. Police determined that the objects were not explosive.

A store clerk recognized Campbell and police went to his home on Alder Street, where he was arrested.

Campbell faces up to 20 years in prison and a $250,000 fine. He will be sentenced after the completion of a pre-sentence investigation by the U.S. Probation Office.