But the navy denied a report in the Wall Street Journal that the marshal and other U.S. officers were dressed as Mexican marines while participating in an operation against organized crime. It said the marshal was only training Mexican naval personnel and wasn't wearing a Mexican uniform.

The navy's statement confirmed the American was wounded on July 11, as reported in the Journal, but the navy gave no information on how the officer was wounded.

According to the Journal story, agents from several U.S. law enforcement agencies joined in an operation aimed at capturing a drug dealer linked to the Beltran Leyva cartel and one of the Americans was wounded when the team was ambushed.

The navy's statement said no official from the United States or any other country has "participated in Mexican navy tactical field operations against organized crime using Mexican uniforms and weaponry."

Under Mexican law, foreign officers cannot carry arms, and officials are sensitive about any foreign participation in law enforcement operations.