The latest documents leaked by NSA whistleblower Edward Snowden reveal that US drone strikes in Afghanistan weren't limited to just al Qaeda and Taliban leaders — they also targeted drug dealers accused of supporting the insurgency.

The papers, obtained by German news magazine Der Spiegel, include a "kill list" that once contained as many as 750 names, including many mid- and lower-level members of the Taliban involved in drug trafficking.

According to the documents, NATO defense ministers decided in October 2008 to start treating Afghan drug lords with ties to the Taliban insurgency as "legitimate targets."

"Narcotics traffickers were added to the so-called Joint Prioritized Effects List (JPEL) for the first time, allowing them to be targeted for strikes," one NSA document states.

The document — dated February 3, 2009, and sent by the chief of NSA Georgia's Southwest Asia Narcotics Division — says the US focused on "narcotics trafficking networks that provide funding, weapons, and logistical support to Taleban elements in Afghanistan."

The NSA, according to the document, "made clear to national and theater leadership that the insurgency could not be defeated without disrupting the narcotics trade." The agency also claimed that they identified some drug dealers as "active insurgent commanders, directing their own fighters in attacks against the coalition, and procuring weapons and improvised explosive device (IED) materials."

The spy agency touted its role in major drug busts, noting that their intelligence led to "the largest single seizure of drugs in history," which captured 237 metric tons of hashish in May 2008. The document says the NSA and GCHQ, the US agency's UK counterpart, provided "real-time intelligence" for more than 20 counternarcotics operations, "netting thousands of kilograms of drugs, several detainees, and weapons."

The document also describes a failed attempt to kill a drug trafficker identified as Mullah Multan when he made "a rare entry into Afghanistan from Pakistan." A strike on Multan's convoy was reportedly conducted "within hours" after he crossed the border. Though he survived and returned to Pakistan, the NSA boasted that Multan lost more than three tons of opium and six men in the attack, "a severe disruption to his narcotics network."

Despite the best efforts of the NSA and coalition forces, the drug trade continues to thrive in Afghanistan. The country now produces nearly double the amount of opium it did in 2000 before the US invasion. With a record 224,000 hectares of land devoted to poppy cultivation, Afghanistan produced 6,400 tons of opium in 2014 — contributing around 90 percent of the global supply.

The use of drone strikes in Afghanistan counterterror operations is well documented, but US and UK authorities have tightly controlled the identities of people targeted by the extrajudicial killings.

It's not exactly a revelation that drug traffickers were targeted by the Pentagon's counterterror operations. In August 2009, a congressional study by the Senate Foreign Relations Committee stated that 50 Afghan drug lords were put on a target list to be captured or killed. The move was an attempt to disrupt the flow of drug money to the Taliban, which has close ties to Afghanistan's lucrative opium trade.

Lt. Col. Patrick Ryder, a Pentagon spokesman, said at the time that, "there is a positive, well-known connection between the drug trade and financing for the insurgency and terrorism."

In January 2009, a classified document also leaked to Der Spiegel showed that US General John Craddock, a top NATO commander, issued "guidance" that provided NATO troops with the authority "to attack directly drug producers and facilities throughout Afghanistan."

The document said that deadly force could be used even where there was no proof to link opium dealers and the insurgency. Craddock wrote that it was "no longer necessary to produce intelligence or other evidence that each particular drug trafficker or narcotics facility in Afghanistan meets the criteria of being a military objective."

But fears that Craddock's order violated international law led to heated discussions within NATO, and it was eventually modified so that targets related to drug production had to be investigated as individual cases.

The latest leaked documents now show that NATO and British forces in Afghanistan planned to target and kill individuals located across the border in Pakistan, despite repeated denials from the UK government that it has conducted drone strikes outside Afghanistan.

"The UK now needs to come clean about its role in executing a 'kill list' that goes far beyond targeting only militant leaders," Jennifer Gibson, a staff attorney at Reprieve, a human rights NGO, said in a statement. "The UK can no longer dodge questions by claiming the drone wars in Pakistan are a 'matter for the states involved.' These documents clearly show the UK is one of those states."