Two U.S. Embassy employees were shot at by the Mexican Federal Police Friday when their vehicle entered an area on the outskirts of Mexico City that was frequented by drug cartels, common criminals and leftist rebels in the past.

The vehicle carrying the embassy employees and a Mexican Navy official was headed to a military installation on official work.

A statement from the embassy said that a Mexican police vehicle opened fire at the U.S. Embassy vehicle carrying a diplomatic number plate by mistake. The diplomatic vehicle was "ambushed by a group of individuals" and "sustained heavy damage" as a result of the attack, the statement said, according to Reuters.

The two embassy officials, one with a leg wound and the other with bullet wounds in the stomach and hand, were hospitalized and were in a stable condition, the Associated Press reported an unnamed government official as saying.

A written statement issued by the Mexican Navy stated that at least four vehicles opened fire at a U.S. vehicle on a highway near the city of Cuernavaca. The driver of the embassy vehicle veered off the road on seeing the Mexican officers with weapons in the car, prompting the police to open fire.

"At that moment those in the ... (police) vehicle opened fire on the diplomatic vehicle," the Navy said in a statement. "Moments later, three other vehicles joined the chase and fired shots at the U.S. Embassy vehicle," Reuters reported.

A U.S. official, speaking on the condition of anonymity, told Associated Press that it was a genuine faux pas.

"Apparently the police were looking for some bad guys and they ran into each other. It looks like it was just a bad mistake ... they just shot and kept shooting," said the official.

The U.S. Embassy in Mexico said that it had been "cooperating closely" with the investigation initiated by the Mexican authorities while the Navy said around 12 officers involved in the incident were being questioned.

"We are working with Mexican authorities to investigate an incident this morning in which two employees of our Embassy in Mexico City came under attack by unknown assailants. They are receiving appropriate medical care and are in stable condition. We have no further information to share at this time," Victoria Nuland, a State Department spokeswoman in Washington, was quoted as saying by Reuters.  

The names of the victims or details about how the shooting took place were not disclosed by the authorities. This is the third case of attack on diplomatic personnel in two years in Mexico.

In 2011, two U.S. Immigration and Customs Enforcement agents were shot in northern Mexico. In 2010, three persons, including a U.S. Consulate employee, were killed in the country.