Mexican authorities have identified a U.S. citizen among the bodies recovered in recent months in mass graves in the northeastern town of San Fernando, the U.S. consulate in Matamoros said Wednesday.

"We wish to express our deepest condolences to the victim's family and condemn this crime in the strongest possible terms," the consulate said in a statement.

The family has decided not to reveal the victim's name due to privacy considerations, according to the consulate, whose personnel are in contact with the victim's relatives and currently offering them consular assistance.

The consulate added that it is in regular contact with Mexican authorities working on the case and is ready to assist them to "bring those responsible for this crime to justice."

It also said another U.S. citizen went missing in that area of northeastern Mexico while traveling by bus in Tamaulipas state on an unspecified date.

The U.S. consulate in Matamoros, located across the Rio Grande from Brownsville, Texas, issued an alert on April 8 warning U.S. citizens of the risk of traveling by bus in Tamaulipas, where a deadly turf battle between the Los Zetas and Gulf cartels has raged since early last year.

In late April, the State Department issued an updated travel warning that called U.S. travelers' attention to various safety risks in different areas of Mexico, especially in the northern border region.

Mexican Attorney General Marisela Morales on June 7 gave an update on the mass grave death toll in San Fernando, saying that 193 bodies have been found in 47 clandestine graves in that town in recent months.

The bodies found in the mass graves in Tamaulipas are believed to be those of people who were kidnapped by the Zetas drug cartel while traveling through San Fernando on buses and were later murdered.

The mass graves were found in the wake of reports that gunmen had forced men off buses headed for Reynosa, Tamaulipas, located across the border from McAllen, Texas, between March 19 and March 31.

Some gangs have resorted to using unusual methods to recruit gunmen because of the high casualties in the war being waged by rival drug traffickers for control of territory, the federal government says.

The incidents involving the buses may have been an attempt to recruit gunmen, according to investigators.

Mass graves containing the remains of victims of drug-related violence have been found in recent years in different parts of Mexico, including the northwestern state of Durango, where 236 bodies were found earlier this year, and the Mexican Pacific resort city of Acapulco, where 14 bodies have been unearthed so far this month.

More than 15,000 people died in drug-related violence in Mexico last year, while nearly 40,000 have perished since President Felipe Calderon declared war on the country's cartels shortly after taking office in December 2006.