Arizona Cops Threatened by Mexican Drug Cartel

June 24, 2010— -- A Mexican drug cartel has threatened police officers in Arizona who confiscated a marijuana shipment, prompting the small town department to warn its officers to remain armed and have radios with them at all times, and keep their body armor handy.

Police and experts believe the warning against the Nogales, Ariz., cops marks the first time that powerful Mexican drug cartels, used to bribing and bullying police south of the border, have targeted U.S. officers.

Jeffrey Kirkham, chief of the Nogales police department, told ABCNews.com that informants had delivered the threats after two off-duty police officers seized 400 pounds of marijuana while horseback riding outside the city earlier this month. The pot was worth about $250,000, he said.

Kirkham said informants have told his police department that off-duty officers should ignore cross-border drug shipments or face retaliation.

The threats appear credible because various informants were able to identify the officers who intercepted the drug load. Kirkham said the threats by Mexican traffickers were the first against local law enforcement on the U.S. side of the border.

"They're getting upset that their product so to speak is not getting to where it needs to be," Kirkham said of the cartels.

The chief said he gave a stern warning of his own to his 63 officers for what to do while they are off duty.

"We met with all the employees and supervisors to make them aware of what was said, and to make sure that they have their body armor and are armed and that their communications equipment is working properly," Kirkham said.

Kirkham attributed the surprising threat toMexico's war on the cartels.

"The pressure is on them from the president in Mexico and that desperation is starting to spill over the border," Kirkham told ABCNews.com.

Attacks by Mexican cartels on American law enforcement officers would be an alarming escalation of the Mexican drug wars. Cartel turf wars have killed more than 23,000 people across Mexico since President Felipe Calderon launched a military crackdown on drug gangs in late 2006.

In the neighboring Mexican city of Nogales, attacks on police officers have become commonplace. A deputy police chief in Nogales, Mexico, and his bodyguard were shot dead in March when gunmen in a pickup truck opened fire on them with assault rifles.

In November 2008, the police chief for Sonora state, which includes Nogales, was ambushed and killed just a few miles south of the Arizona border.