The U.S. Coast Guard was conducting a training exercise on the Potomac River this morning, which initially caused a scare due to its proximity to the Pentagon during Sept. 11 memorial ceremonies.

CNN originally reported that the U.S. Coast Guard had opened fire on a boat in the Potomac River this morning, but the incident was actually a training exercise. Given the exercise’s timing and location, on the morning of September 11, near the Pentagon, at a time when President Obama was laying a wreath to honor the victims of 9/11, the incident initially caused panic across the area.

10:31 a.m.: The Washington Post now has a banner up calling the incident a “Coast Guard training exercise.” Given how calm everything looks (and how much CNN is now hedging on their original report), this seems likely, though there’s no story as yet to back up the Post’s assertion. Who in their right mind would schedule a Coast Guard training scenario on the Potomac River, right by the Pentagon, on Sept. 11?

10:46 a.m. Coast Guard Chief Keith Moore finally confirmed with the AP that no shots were actually fired as part of the exercise, contrary to CNN’s earlier report. D.C. Police officials have also said that they were told ahead of time that the Coast Guard’s activity on the Potomac River this morning was a training exercise.

10:49 a.m. And, here’s the Post’s story.

11:59 a.m. ABC News’ Jake Tapper writes how White House Press Secretary Robert Gibbs said that he blames CNN, not the Coast Guard, for today’s scare. ‘He said media should “check before reporting” such events, and suggested other training exercises are likely going on right now that we don’t know about, and rejected any comparison with the Air Force One flyover of Manhattan.’