Web Posted: 01/29/2005 12:00 AM CST

Dane Schiller and Guillermo Contreras
San Antonio Express-News

MEXICO CITY — The FBI warned all federal agents Friday that a Mexican drug cartel has 250 armed men on the border near Matamoros and is planning to kidnap two federal agents in the United States and smuggle them into this nation, where they'll be murdered.

The FBI office in San Antonio declined to discuss the source of the information, but issued a written bulletin warning of an "immediate threat to law enforcement personnel."

The bulletin goes on to say the "extremely violent" drug-smuggling organization known as the Gulf Cartel already sent a contingent that are believed to have valid visas to enter the United States.

"Due to the nature of this immediate threat, all law enforcement personnel are being cautioned to ensure appropriate measures are taken as well as to keep a high degree of vigilance," the bulletin states.

Rene Salinas, a spokesman for the FBI in San Antonio, said the information is "uncorroborated," but that federal agents and police are being told to use extra caution.

"We are trying to see if it is legitimate," he said of the murder-kidnap plot.

"It could be DEA (Drug Enforcement Administration), ATF (Alcohol, Tobacco and Firearms) or Border Patrol. It could be anybody," he said of potential victims.

He stressed the FBI bulletin was "law enforcement sensitive" and not intended for the public.

The prospect of a U.S. federal agent murdered in Mexico conjures up memories of DEA agent Enrique Camarena Salazar, who in 1985 was snatched off the streets of Guadalajara and tortured to death by drug traffickers.

Agustín Gutiérrez Canet, the international spokesman for Mexican President Vicente Fox, said any possibility of a threat by the Gulf Cartel can't be underestimated.

"These kind of criminals are not playing games," he said. "This group is very dangerous and must be taken seriously, but let us hope it is only a false alarm."

It wasn't immediately clear if the FBI had sought assistance from Mexico in evaluating the threat.

An FBI agent who works along the U.S.-Mexico border said the threat was discovered as agents investigated illegal activity in the region.

Agents are accustomed to threats, but this was different, he said.

"It had more specificity than usual, which caused us a little more concern then say a normal threat would," he said. "All of our agents have been urged to use extreme caution and to work in teams until this is resolved."

T.J. Bonner, president of the National Border Patrol Council, said it was too soon to know how the agency would address the threat, but options include keeping agents in pairs, staying in closer contact and changing routines.

"Unfortunately, in most incidents, most agents are out there alone, like sitting ducks," he said.

The bulletin couldn't come at a more awkward time for U.S.-Mexico relations, as President Fox on Thursday blasted U.S. Ambassador to Mexico Tony Garza for complaining Mexico was not doing enough to prevent murders, kidnapping and other drug-cartel violence.

In a letter to the Foreign Ministry and attorney general, Garza said violence is so rampant along the U.S.-Mexico border that it threatens U.S. citizens visiting this country.

Fox responded that no foreign country had the right to judge Mexico's efforts and that Mexico was fighting the cartels on numerous fronts.

Also earlier this week, Fox dispatched about 700 federal police and an uncertain number of soldiers to increase security in the vicinity of the Texas-Mexico border cities of Matamoros, Reynosa and Nuevo Laredo.

As part of the effort to increase pressure on jailed cartel leaders, who are believed to still operate their empires behind bars, federal police took over operations at three maximum security prisons, including facilities in Matamoros, Guadalajara and just outside Mexico City.

With regard to the FBI memo, there was no response from the Mexican government. The Mexican attorney general's office said it had no immediate information on the threat.

U.S. Embassy spokesman Jim Dickmeyer said the bulletin was not generated to heap more criticism on Mexico.

"People do not do this for political reasons, they do it for security reasons," Dickmeyer said. "No one is trying to be alarmist."

In related action, the Air Education and Training Command, based at Randolph Air Force Base in San Antonio, is advising personnel to avoid Mexico, based on State Department concerns.

"We did not tell them they cannot go, just that this is the situation — be advised," Lt. Col. Johnn Kennedy said.