Colombia’s FARC guerrillas have allegedly purchased at least seven anti-aircraft missiles that experts say could threaten U.S.-provided helicopters essential to the South American country’s fight against the rebels.

Peruvian prosecutors detailed the purchases when they charged a dozen people in December with buying hundreds of weapons from crooked Peruvian security force officials and delivering them to an arms buyer for the Revolutionary Armed Forces of Colombia, or FARC.

The missiles could complicate Colombia’s decades-old civil war, where the military has made strong gains in recent years by deploying a fleet of U.S.-provided transport and attack helicopters for swift raids on FARC targets.

Colombian military analyst Alfredo Rangel said that if the Peruvian allegations are true, the handful of missiles “could be used to shoot down a couple of helicopters,” but “their impact would not be very significant.”

The weapons likely would be devoted to the defense of the FARC’s top leaders but “would not allow the FARC to shift to the offensive or alter the balance of power against the government forces,” he told El Nuevo Herald in a telephone interview.

The Peruvian prosecutors’ records detail the sale of at least four Russian-made Strela and Igla ground-to-air missiles between May and October 2008 and another three in 2009, “each one for the sum of 45,000 US dollars.”

They were sold by Jorge Aurelio Cerpa, a Peruvian air force official, and were delivered to Freddy Torres, an Ecuadorean who had been buying weapons for the FARC since 2007, according to the records. They and nine others were arrested and charged with collaboration with terrorism, and several have confessed.

Peruvian army and police officers also sold Torres hundreds of hand grenades for up to $60 apiece, 40-50 heavy machine guns for $19,000 each and tens of thousands of rounds of ammunition, according to the records, first published by the La República newspaper in Lima.

Torres, who was arrested Dec. 19 on Peru’s northern border with Ecuador, was paying $150,000 to $200,000 for arms deliveries “every 15 or 20 days,” a copy of the records provided to El Nuevo Herald showed.

HEAT-SEEKING

 But the most significant purchases were the heat-seeking Strela and Igla missiles, which can be carried by one person and fired from the shoulder. U.S. officials have been particularly concerned that such weapons could fall into the hands of terrorists.

The Strela and older Igla missiles have a maximum range of about three miles and are highly effective against slow-flying aircraft not equipped with electronic countermeasures. It’s not clear whether Colombia’s U.S.-made UH-1H and Blackhawk helicopters have the appropriate countermeasures.

Hoping to reverse its recent setbacks, the leftist FARC, has made it a priority to obtain the man-portable missiles.

Such missiles would allow the rebels to deal “forceful blows to the enemy’s air power,” the FARC leader known as Alfonso Cano wrote in an Aug. 16, 2009 e-mail intercepted by Colombian military intelligence and published in that country’s media.

The e-mail, a 14-point plan to improve the FARC’s fighting abilities, said the rebels should set aside $5 million to $6 million to buy weapons for its estimated 9,000 fighters, who finance their war largely through cocaine trafficking and kidnappings.

The FARC’s need for missiles was also mentioned in an e-mail found in computers captured when the Colombian military raided a rebel camp in neighboring Ecuador in 2008 and killed the top FARC commander known as Raúl Reyes.

“The anti-aircraft weapons are already, for us, an urgent necessity,” said the e-mail between two rebel commanders, also published in the Colombian media.

While Colombian and U.S. officials have long been concerned about the possibility that the FARC could obtain the ground-to-air missiles, most of the unease to date had focused on Venezuela, where leftist President Hugo Chávez has long expressed sympathy for the guerrillas.

BUYING SPREE

Chávez has been on an arms-purchasing spree since 2006, buying $6 billion worth of Russian jets, helicopters, tanks and Igla-S missiles — also known as SA-24, the latest and most sophisticated version of the weapons — for what he calls the defense of his country from planned U.S. attacks.

The U.S. Treasury Department accused a former Chávez cabinet minister and two generals in 2008 of helping the FARC with weapons, finances and drug-trafficking, and ordered the seizure of any of their assets found in the United States.

But the Peruvian case focused new attention on that country, which bought 633 IGLA-1 missiles, also known as SA-16s, from 1992 to 1996, and 500 older Strela 2 missiles, also known as SA-7s, from 1978 to 1981, according to the Stockholm International Peace Research Institute, which tracks weapons purchases around the world.

The prosecution documents make no mention of any ideological affinity between the FARC and the Peruvian military officers who sold the weapons — after writing them off the books as spent in training exercises or junked because of old age — indicating that they were doing so purely for money.

Nicaragua voluntarily destroyed about 1,400 Strela 2 missiles after the war between the Soviet-backed Sandinista government and U.S.-backed contra guerrillas, but U.S. officials are still offering the current government $5 million to destroy its remaining 600.