An armored U.S. Embassy vehicle is seen riddled with bullets, most concentrated around the passenger-side window, after it was attacked by unknown assailants on the highway leading to the city of Cuernavaca, near Tres Marias, Mexico, on Aug. 24, 2012. Two U.S. government employees were shot and wounded in an attack on their vehicle south of Mexico City on Friday, a law enforcement official said. (Alexandre Meneghini/AP)

Two U.S. government employees were wounded in a hail of gunfire south of Mexico City on Friday in what law enforcement officials described as a wild shooting spree that involved Mexican federal police.

The two wounded Americans were riding in a U.S. Embassy car, a sport-utility vehicle with diplomatic plates, when they came under heavy fire on a highway between the capital city and Cuernavaca. According to Mexican media reports, the vehicle was struck by more than 30 bullets.

The two Americans were driving with a captain from the Mexican Navy en route to a military training camp when they came under fire, according to the Mexican attorney general, who said federal police officers were involved in the shooting.

Twelve federal police officers have been detained and ordered to give statements about their role in the attack.

If federal police pulled the trigger, it marks a major embarrassment for the Mexican government, which has received millions of dollars in equipment and training for the justice system as part of a $1.6 billion anti-drug aid package from the U.S. government.

According to a statement by the Mexican Navy, the two Americans were headed toward a training camp at 8 a.m. Friday when they were confronted by another vehicle with men brandishing weapons. The SUV containing the Americans refused to pull over and attempted to return to the highway. Soon three more vehicles were involved in a chase and the U.S. Embassy vehicle came under heavy fire.

One Mexican official, who declined to be identified, said the federal police thought the occupants were adversaries who were fleeing.

Federal police were operating in the area looking for people who had stolen a vehicle the day before from the head of the National Museum of Anthropology and History, the Mexican Navy said.

U.S. officials confirmed that two wounded Americans were taken to a hospital in Cuernavaca, where they were in stable condition. At least one of them was attached to the U.S. Embassy and the other on temporary assignment in Mexico.

The Associated Press reported that one man had a wound to the leg and the other was hit in the stomach and hand.

U.S. Embassy officials declined to identify the wounded U.S. employees. The Drug Enforcement Administration, FBI and Immigration and Customs Enforcement said the men did not work for their agencies. The Pentagon said the wounded were not soldiers. CIA spokeswoman Jennifer Youngblood declined to comment and referred reporters to the State Department.