By EILEEN SULLIVAN

Associated Press

WASHINGTON -- The Coast Guard conducted a training exercise in the Potomac River near the Pentagon amid Sept. 11 commemorations today, sparking confusion that scrambled FBI agents and led the nearest airport to briefly ground flights.

Coast Guard Chief Keith Moore said today no shots were fired as part of the exercise in the river. Media reports suggested shots had been fired in the river and showed vessels circling in the water, near the bridge where President Barack Obama's motorcade passed as he traveled to a Sept. 11 memorial at the Pentagon this morning.

Departures from Reagan National Airport were halted as a precaution at 10:08 a.m., then resumed at 10:30 a.m., Federal Aviation Administration spokeswoman Diane Spitaliere said. The airport borders the Potomac.

A law enforcement official, speaking on condition of anonymity, said federal agents scrambled to the river scene after the initial reports, because the local FBI office had not been told ahead of time about the exercise.