MEXICO CITY (CNN) -- Unknown gunmen attacked an American diplomatic vehicle south of Mexico City on Friday morning, wounding three people, a Mexican military official told CNN Mexico.
Reports conflicted over the nationalities of the victims. The Mexican official said three Mexican marines were wounded, some Mexican reports said two of the wounded were Americans, and a U.S. government official said the three victims were Americans. The latter official could not be identified because that official was not authorized to speak to the news media.
The motive behind the attack on the U.S. vehicle, which was on a diplomatic mission, was not immediately known.
Gunmen inside what was described as a Mexican federal police vehicle fired upon a U.S. Embassy vehicle, said the Mexican official, who declined to be named for security reasons.
The wounded occupants were taken to a hospital in Cuernavaca.
The Drug Enforcement Administration said that a U.S. diplomatic vehicle had been "shot up" in Mexico but said no DEA officers were involved.
The U.S. State Department said it was aware of the reports but had no immediate comment.
The vehicle was attacked on a highway between Mexico City and Cuernavaca, near the town of Tres Marias.
Mexico's federal police said that its personnel were not involved in the shooting. Their forces appeared at the scene only after the shooting to secure the perimeter, police said.
CNN's Jill Dougherty and Terry Frieden contributed to this report.