Report finds Mexico is primary source of fentanyl in U.S.

(KYMA, KECY/ NBC News) - A bipartisan report from a Congressional Commission says the primary driver of the opioid epidemic today is illicit fentanyl.

Fentanyl is a synthetic opioid that's up to 50 times more potent than heroin.

The report from the "Commission on Combating Synthetic Opioid Trafficking" was released early Tuesday morning.

The report found that Mexico is the principal source of fentanyl in the United States, with smuggling across the southwestern U.S. border being the primary method of transport.

Still, the report noted an increase in the use of America's domestic mail system to move fentanyl within the country.