Developing: The Coast Guard was conducting a training exercise in the Potomac River moments before President Obama and his motorcade crossed a nearby bridge.
Coast Guard Chief Keith Moore said Friday no shots were fired as part of the exercise. Media reports suggested shots had been fired in the river.
Obama had traveled to the Pentagon for a ceremony commemorating the eighth anniversary of the Sept. 11 terrorist attacks.
A spokesman with the Department of Homeland Security told FOX News that the agency is "monitoring the situation in the Potomac closely with the U.S. Coast Guard"
"The Coast Guard has boats in the area," spokesman Matt Chandler said. "We are working to confirm more information on the incident. At this time, we cannot confirm shots fired or any law enforcement action taken. We will provide updates as they become available."
