INCB said in its annual report the record-setting level of poppy cultivation was a threat to Afghan national security.
Afghanistan accounts for more than half of the world's opium, a heroin precursor. Last year, the U.N. Office on Drugs and Crime said opium cultivation in Afghanistan increased 36 percent from 2012.
"The drug control situation in Afghanistan will not improve unless substantial, sustainable and measurable progress is made by the government in anti-drug trafficking, alternative development and drug demand reduction," the INCB report, published Wednesday, said.
The U.N. Food and Agriculture Organization said farmers in the north of Afghanistan, however, are turning to licit crops as an alternative to opium cultivation. The FAO says nearly half of Afghanistan's 35 provinces are free of opium farms.
Nevertheless, INCB said it was "seriously concerned" by the general increase in opium cultivation.
"Record-setting poppy cultivation and opium production in 2013 threaten an already fragile security situation in Afghanistan, and neighboring countries, at a time when international security forces begin their planned withdrawal," its report said.