MEXICO CITY - Mexico's foreign secretary called a State Department alert to Americans traveling along the border "exaggerated" and said his nation has proved that it is successfully combating violence and drug trafficking in the region.

Luis Ernesto Derbez's comments late Wednesday to Mexico's Televisa television network came in response to the U.S. alert and an accompanying letter from U.S. Ambassador to Mexico Tony Garza, both issued earlier Wednesday.

In the letter, addressed to Derbez and Mexican federal Attorney General Rafael Macedo de la Concha, Garza said he was concerned that growing drug-related violence and kidnappings on the Mexican side of the border would have a "chilling" effect on trade and tourism between the countries.

Violent criminal activity, including killings and kidnappings, has increased in Mexico's northern border region amid a growing war between drug traffickers struggling for control of the area.

"U.S. citizens should be aware of the risk posed by the deteriorating security situation," the State Department advisory said.

The announcement came just days after Mexico sent federal police officers to patrol the streets of border cities from Matamoros to Nuevo Laredo and Reynosa, all of which share a border with Texas, at the request of local authorities who said the crime had spun out of control.

It also comes as officials crack down on top-security federal prisons housing reputed drug traffickers, who allegedly have continued to operate their businesses and direct bloody turf battles from behind bars.

Interior Secretary Santiago Creel told a news conference late Wednesday that Mexico "is determined to wage a head-on battle" against drug traffickers and organized crime groups operating on the border.

Derbez took a harder line, telling Televisa that he and other officials would provide a "punctual, very concrete response to these types of statements, which seem to us, in large measure, exaggerated, and outside the scope of reality, because the Mexican government has taken concrete actions" against criminal groups operating along the border.

In his letter, Garza noted the great majority of border-violence victims are Mexican citizens, but added that "the elevated level of violence generally has resulted in greater risks to the thousands of American citizens visiting and passing through the border region every day. Increased numbers of murdered and kidnapped Americans in recent months bear this out."