Washington shooting was exercise

The US Coast Guard, on high alert for the anniversary of the September 11 attacks, fired 10 rounds on a suspicious boat on the US capital's Potomac River, CNN television reported.

However it was later reported that the incident was part of an exercise, causing outrage on TV networks because it coincided with September 11.

It was not immediately clear if the boat posed any danger to Washington, as President Barack Obama for the first time led ceremonies to mark the eighth anniversary of the attacks.

The vessel was challenged in a restricted part of the river, adjacent to the Pentagon where Obama was attending a ceremony to mark the 2001 attacks, CNN said.

Contacted by AFP the coast guard said they could not immediately confirm the incident, and were checking the details. Police declined any comment saying they were not handling the situation.