According to the United Nations Office on Drugs and Crime (UNODC), more than 90 percent of the world's opium originates from Afghanistan, despite the presence of foreign troops in the country.

The UN reports says the Taliban currently generate more income from the drug trade than when they held power in the country in the 1990s. The insurgents are believed to earn between 60 and 110 million euros each year, allowing them to "fund a war machine that is becoming technologically more complex and increasingly widespread", says UNODC Executive Director Antonio Maria Costa.

The opium produced in Afghanistan, a thick paste produced from poppies, is used to make heroin. About two thirds of the opium is turned into heroin before it leave the Central Asian country, while the rest is trafficked as opium. Less than two percent of that opium and heroin is seized by authorities before it leaves Afghanistan.

Nearly half of the world's heroin is consumed in Europe and Russia, while 42 percent of the world's opium users are in Iran. The two drugs cause up to 100,000 deaths a year, 30,000 of which occur in Russia.