BALTIMORE — An underground fire and an hourslong power outage in downtown Baltimore snarled Friday morning’s commute and closed the city’s two courthouses.

Firefighters called to North Charles Street on Thursday night for a report of an underground fire and a possible explosion found fire coming from one manhole cover, according to a news release from the Baltimore Office of Emergency Management.

The fire affected underground electrical conduits along North Charles Street and power was shut down in the area to assist in extinguishing the fire, officials said. Firefighters used water and dry chemical extinguisher to extinguish the visible fire.

Sara Hennessey told The Baltimore Sun she was working as a server at Mick O’Shea’s nearby when she heard the explosion.

“First, I heard a loud bang. I looked outside and saw what I thought was fog,” she said. “The firefighters showed up to the restaurant and had us leave through the back door. I thought it was a truck going over something on the first bang. There were two bangs.”

Several city buildings were affected by the outage, with essential buildings running on emergency power. The Mitchell and Cummings courthouses were closed Friday because of the outage.

Light rail service through downtown was suspended for a time, but resumed Friday morning and city transportation officials urged people to avoid the area.

Power was restored to the downtown area by 7:30 a.m., but 16 buildings were still without power, the city’s chief administrative officer posted on social media.