Opium poppy cultivation in Afghanistan hit record levels in 2013 despite counter-narcotics efforts by Washington, a US report says.
The special inspector general for Afghanistan reconstruction said the US had spent $7.6bn (£4.72bn) over 13 years trying to eradicate the plant.
A number of agencies gave to the funds aimed at supporting narcotics officers and helping farmers change livelihoods.
Despite this, Afghanistan grew 209,000 hectares of the plant in 2013.
A UN body says the value of this crop was nearly $3bn (£1.86bn), up 50% from 2012.
"With deteriorating security in many parts of rural Afghanistan and low levels of eradication of poppy fields, further increases in cultivation are likely in 2014," said the US inspector general, John Sopko.
The report also found that areas such as Nangarhar in the east of the country, which was previously declared "poppy-free", are cultivating the plant again.
It is believed that affordable deep-well technology might be responsible for the surge.
Over the past decade, the wells have turned 200,000 hectares of desert into farming land. Much of this is being used to grow opium poppies.
Afghanistan is responsible for producing about 80% of the world's opium.
Profits from the trade help fund corruption within the country, maintain criminal networks and support terrorist groups such as the Taliban.
The report comes as President Ashraf Ghani, appointed at the end of September, tries to usher in a new era for Afghanistan.