"One small (Iranian) craft was coming toward it, and it stopped after the Whidbey Island fired warning shots," said the official, speaking on condition of anonymity because of the sensitivity of the issue.
It was the first official confirmation that the United States had fired warning shots in any recent confrontation with Iran in the Gulf.
In the second incident that month, the USS Carr encountered three small Iranian craft on Dec. 22, two of which were armed, said the official. The USS Carr did not fire warning shots, but sent warning blasts on the ships whistle, which caused the boats to turn around.
The reports come a day after the United States lodged a formal diplomatic protest with Iran over an incident Sunday in which Iranian speedboats harassed U.S. warships in the Persian Gulf.
Adm. William J. Fallon, the top U.S. military commander in the Mideast, said Friday that Iran runs the risk of triggering an unintended conflict if its boats continue to harass U.S. warships in the strait.
