The growth in abuse of heroin is now considered the number one drug threat by the nation's police, overtaking methamphetamine, according to a new survey by the Drug Enforcement Administration, NBC News reported.

"Heroin availability is up across the country, as are abuses, overdoses, and overdose deaths," says the 2015 National Drug Threat Assessment Summary, released Wednesday.

Law enforcement seizures of heroin have nearly doubled in the past five years, and the number of heroin users is up 51%, according to the latest findings from the Substance Abuse and Mental Health Services Administration.