Kabul, Afghanistan ? Russian counternarcotics agents teamed up with U.S. and Afghan forces in an unprecedented joint raid that destroyed nearly $56 million worth of heroin near the Pakistani border, officials said Friday.

The seizure of four drug labs nestled in thick vegetation along a dusty gray moonscape in Nangarhar province came less than a week after Russia’s anti-narcotics chief accused the U.S. of failing to dismantle such labs and slow down the flow of heroin into Russia.

The 932 kilograms (about one ton) confiscated in Thursday’s raid is unlikely to have a significant impact on Afghanistan’s drug trade. The country produces enough raw opium to manufacture 360 tons of heroin a year, according to the U.N. Office on Drugs and Crime.

But the level of cooperation between U.S. and Russian forces was significant and suggested an improvement in relations between the former Cold War foes, two decades after U.S.-financed Afghan militias chased the Soviet military out of this country.

The two nations nowadays occasionally cooperate on terrorism and drug issues, but Moscow has offered only lukewarm support for the U.S.-led war in Afghanistan. So far, Russia has limited itself to providing its territory for U.S. military transit, turning down requests to provide helicopters and training for pilots or to train counter-narcotics police.

Nevertheless, the export of Afghan drugs is an issue of paramount concern to Russia, which now has 2 million opium and heroin addicts. Moscow had been urging the U.S. military to take action against Afghan drug labs, which process unrefined opium into heroin or morphine.

Nine helicopters and 70 men were involved in the raid, said Russian anti-narcotics chief Viktor Ivanov, adding that his agency told the U.S. where the labs were located.

Ivanov said four Russians were involved in the raid, and that Russia may increase the number of its drug agents in Afghanistan in the future.

Photos shot at the scene and provided by the U.S. Drug Enforcement Agency show men in military uniform carrying metal canisters across a drab landscape. Stacks of brown sacks lie near basins with white residue and oil drums painted black.

An Afghan official said the labs were in a narrow valley high up in the mountains. He spoke on condition of anonymity because he was not authorized to speak to the press.

Four labs were shut down in the operation, which involved three branches of Afghan law enforcement as well as NATO, the U.S. and the Russians, said U.S. Embassy spokeswoman Caitlin Hayden in Kabul. A DEA press release said the raid originally targeted one lab but then found three others hidden by vegetation.

In addition to the 932 kilograms of heroin, agents seized 156 kilograms of opium in the raid in the village of Zerasari, part of the district of Achin. It takes about 10 tons of opium to make one ton of heroin.

U.S. officials said the heroin had a street value of $55.9 million. Ivanov gave much higher figures: He was quoted by Russian media as saying the seized drugs were worth at least $250 million and probably even up to $1 billion.

Last weekend Ivanov used an interview with The Associated Press to criticize the U.S. for not taking action to stem a flow of Afghan heroin into Russia. He said that months ago he provided U.S. officials in Kabul with the coordinates of 175 laboratories where heroin is processed but that the U.S. failed to act.

In the interview, he said American officials had told him they were awaiting U.S. military approval to raid the labs.