The United States has placed 50 suspected Afghan drug traffickers with ties to the Taliban on a Pentagon list of people to be captured or killed.
A report for the Senate Foreign Relations Committee released on Monday, said major drug traffickers who help finance the insurgency in Afghanistan "are likely to find themselves in the crosshairs of the military."
It says "50 are now officially on the target list to be killed or captured."
The Pentagon has confirmed it is "targeting terrorists that are linked to the drug trade." It says they are "legitimate targets."
The report says Afghanistan's opium industry produces more than 90% of the world's heroin and generates $US3 billion per year in profits.
The Senate report said many military and civilian officials from the United States, Britain, Canada and other countries operating in Afghanistan believe the Taliban cannot be defeated without cutting off the money from Afghanistan's opium industry.
The document was first reported in The New York Times. The paper says two American generals have told the US Congress that the policy is legal under the military's rules of engagement and international law.
The BBC reports US policy in Afghanistan focused on destroying poppy crops for many years.
But in March, US envoy Richard Holbrooke said that efforts to eradicate opium poppy crops in Afghanistan had been "wasteful and ineffective".
There are now about 101,000 foreign troops in Afghanistan. US forces number about 62,000.