An explosion aboard a cargo vessel near the site of the collapsed Francis Scott Key Bridge late Monday is under investigation, Baltimore and federal officials said.

Part of a Liberian cargo vessel exploded, causing a fire in a portion of the ship that was located south of Fort Carroll, according to Baltimore City Fire Department.

At 6:30 p.m., Baltimore City Fire Department firefighters responded to reports of a commercial vessel exploding in the Patapsco River .

The ship, a 751-foot commercial cargo vessel named W-Sapphire, showed signs of a fire consistent with an explosion, according to Baltimore City Fire Department spokesperson John Marsh.

“Firefighters responded by both land and water, including the department’s fireboats,” Marsh said. “The vessel remained afloat and was being

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