Afghan authorities have failed to implement basic anti-money laundering procedures mandated by the U.S., potentially allowing large quantities of untraceable cash to flow to terrorists and drug runners, according to a report released Tuesday by the Special Inspector General for Afghanistan Reconstruction (SIGAR).

Rampant money laundering remains a persistent and “deeply troubling” issue in Afghanistan despite U.S. attempts to trace the outflow of funds from Kabul International Airport (KBL), the country’s main hub, the report said.

“While large cash movements are typical in Afghanistan because it is a cash-based economy, these bulk cash flows raise the risk of money laundering and bulk cash smuggling—tools often used to finance terrorist, narcotics, and other illicit operations,” according to the report, which was addressed to Secretary of State Hillary Clinton and U.S. Ambassador to Afghanistan James Cunningham.