FBI Director James Comey James Brien ComeyMichael Cohen book debuts at top of bestseller list Trump offered Kelly FBI director's job, demanded loyalty: report Tale of two FBI cases: Clinton got warned, Trump got investigated MORE says Mexican drug cartels are behind America’s epidemic of “highly, highly pure” heroin.

“Drug trafficking is a business, and when you reduce costs of transportation, you’re able to lower the price and increase the purity,” he said Wednesday in Glen Allen, Va., according to Fox News.

“We cannot arrest our way out of this problem,” Comey added at a community opioid summit.

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“Our job is to try to crack down on the supply, literally, to be very blunt, to drive up the price to make it less and less attractive for people who are addicted to pills to move to heroin.”

Comey said Mexican cartels are cutting overhead costs by ramping up production in Mexico rather than relying on production from South America.

Mexican cartels have since cornered America’s heroin market, he added, with traffickers even selling the drug at a loss in order to gain market share.

Comey was joined at Wednesday’s summit by Chuck Rosenberg, the acting administrator of the Drug Enforcement Administration.

Rosenberg and Comey agreed that the widespread abuse of prescription opioid painkillers is partially responsible for a U.S. heroin boom.

“Sometimes we use words like ‘epidemic’ or ‘unprecedented’ or ‘historic’ in ways that are not really accurate,” Rosenberg said, noting 4 of 5 heroin users begin with prescription painkillers. "This is unprecedented. This is an epidemic."