(CNN) -- Enough Afghan opium to supply world demand for two years has effectively gone missing, with the Taliban suspected of stockpiling supplies in a bid to corner the market, the United Nations Office for Drugs and Crime (UNODC) has revealed. Pakistani customs officials destroy contraband narcotics on the border with Afghanistan. Afghanistan is the world's leading narcotics supplier. Earlier this month, a U.N. study revealed Afghanistan's opium production had dropped dramatically this year partly because of new aggressive drug-fighting tactics in the country. According to the UNODC report, production dipped by 10 percent this year while cultivation fell by 22 percent.
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Recent study revealed Afghan opium production has dropped dramatically
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U.N. says this should be treated with caution as country has been over-producing
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Taliban suspected of stockpiling large amounts of opium "as credit"
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U.S. has warned of growing link between Taliban and the drug trade
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