Sept. 11, 2009 -- U.S. Coast Guard and law enforcement sources told ABC News that reports of shots being fired on the Potomac River in Washington, D.C., this morning that set off a scramble by the media and law enforcement agencies, were only a routine training exercise.
Several media organizations reported around 10 a.m. that shots had been fired by the Coast Guard on a suspicious vessel in the Potomac River. Ten rounds of ammunition were fired, according to CNN, which also reported that the boat was in restricted space.
U.S. Coast Guard Sector Baltimore Petty Officer John Edwards told ABC News it was "absolutely" a training exercise and the Department of Homeland Security confirmed that no live ammunition shots were fired.
The Homeland Security department is working closely with the Coast Guard to determine what exactly happened on the Potomac River.
The reports came less than an hour after President Obama traveled across the Potomac River for an event at the Pentagon to commemorate the eighth anniversary of the Sept. 11 attacks.
Although weapons are mounted on the boat, they are not loaded, Coast Guard sources told ABC News.
Pentagon officials told ABC News they did not have any information about what was happening in the Potomac River because it was occurring off the portion of the river that runs near the Pentagon. Officials said they knew only what they were seeing in media reports.
The Associated Press quoted a Federal Aviation Administration spokeswoman as saying that departures from Reagan National Airport were halted shortly after 10 a.m. as a precaution while the confusion was being sorted out.
The Coast Guard said it would hold a news conference in the afternoon to discuss the incident.
ABC News' Jason Ryan and Martha Raddatz contributed to this report.