The U.S. Drug Enforcement Administration, along with U.S. military forces and law enforcement officials from Afghanistan and Russia, have seized nearly $60 million worth of heroin after raiding a series of “clandestine drug labs” in northeastern Afghanistan, according to a senior DEA official.

The raids, launched Thursday as part of “Operation Tar Pit,” targeted three heroin labs and a “morphine conversion” lab in Nangarhar Province, which the U.S. government says was Afghanistan’s center of opium production until 2005.

In all, the raids have netted a metric ton of heroin and various components and equipment used to manufacture the drug.

“We don’t often get stuff in this large of a quantity,” one DEA official said.

The targets were chosen based on information from a confidential source, and the labs targeted have been “connected” to a “significant narcotics trafficker” in the Nangarhar Province, according to a DEA source.

According to the source, the raids aimed to “disrupt heroin production in Nangarhar,” produce “future intelligence-directed interdiction operations,” create a “credible perception of risk” within the drug trade, and “instill confidence” in the local populace “regarding the effectiveness of Afghan counter-narcotics forces.”

Nangarhar Province, with its capital city of Jalalabad, is densely populated and rich in natural resources, including high-quality marble and substantial water resources, according to the U.S. Agency for International Development. The province now provides significant amounts of grains, fruits, and vegetables throughout Afghanistan, the agency says on its website.