An underground fire Sunday shut down roads in downtown Baltimore and wiped out power and internet for thousands of city residents.

The 300 blocks of North Charles Street and St. Paul Street and several nearby blocks remained closed Sunday afternoon, snarling traffic as tens of thousands of people prepared to head to M&T Bank Stadium to watch the Ravens take on the Buffalo Bills.

Flames leapt from one manhole cover and smoke rose from several others, the Mayor’s Office of Emergency Management wrote in a news release. Manholes might have exploded, according to the release. One firefighter suffered an injury and was taken for treatment, a Baltimore City Police spokesman said.

The cause of the fire was unclear Sunday. The interior of Viva Books inside Brown’s Arcade in the 300 block of N. Charles St. was destroyed, with bookshelves and furniture wrecked and a large, charred hole in the wooden floor. The shop owner could not immediately be reached for comment.

Officials shut off power in the area to enable firefighters to attack the blaze, according to the news release, forcing the University of Maryland Medical Center Midtown Campus to operate on generator power.

Baltimore City Fire Department and Baltimore Gas and Electric crews “are continuing to safely work together to cycle power through the impacted area,” according to the statement. “At present, threats to the public have been mitigated.”

About 3,300 customers were without power in the area at 6 p.m., according to BGE’s outage map.

The fire affected fiber-optic cables that provide local and statewide internet service, the Enoch Pratt Free Library posted on social media. The library said it will be closed Monday.

The outage also led the library system to cancel a Monday talk with Tui T. Sutherland, author of the popular Wings of Fire series for children.

Traffic signals also were out across the Mount Vernon and Midtown areas, including between Baltimore Street and Madison Street on Charles Street and other main thoroughfares.

BGE and Xfinity crews were working below the streets Sunday afternoon.

Baltimore Banner reporters Christina Tkacik and Meredith Cohn contributed to this report.