Heroin deaths are spiking in the U.S., concerning lawmakers who proclaim it an epidemic and public health issue.

Between 2012-13, the number of U.S. drug overdose deaths resulting from heroin spiked from 5,900 to 8,200, said Michael Botticelli, director of the White House Office of National Drug Policy Center.

"I've been with [the] DEA almost 30 years, and I have to tell you, I've never seen it this bad," Jack Riley, acting deputy administrator of the Drug Enforcement Administration, said at a House judiciary subcommittee hearing Tuesday.

He offered more grim statistics. He told lawmakers that of the 120 drug overdose deaths seen per day in the U.S., more than half are from heroin and prescription painkillers.

That has lawmakers and White House officials concerned.

"The stark increase in the number of people using heroin in recent years has become a significant public health issue in our country," Botticelli said.

"It is no exaggeration to say that heroin use has reached epidemic levels across this nation, including in my home state of Virginia," Judiciary Chairman Rep. Bob Goodlatte, R-Va., said, adding that one Virginia county he represents has seen 11 heroin overdoses this year.

The sharp uptick in heroin use isn't limited to any specific demographic or geographic bounds, lawmakers and witnesses said. "Heroin can be found in virtually every corner of our country, in places I've never seen it, large and small, urban and rural," Riley said.

Botticelli highlighted heroin's prevalence in rural areas and "small town America."

Botticelli and Riley highlighted the two major reasons for the soaring heroin use.

A major influence is the prevalence of prescription drugs, with "the vast overprescribing of prescription drugs and easy access" to them fueling the heroin epidemic, Botticelli said.

A recent study from the Centers for Disease Control and Prevention found that a person was 40 times more likely to be a heroin abuser if he had previously abused painkilling drugs. Eighty percent of new heroin users have previously used opioid drugs, Botticelli said.

Lawmakers and witnesses both explained that once a user runs out of prescription medicines or the ability to buy them, they turn to heroin, which is much cheaper.

"Once someone is addicted to a prescription opioid, the need to satisfy their addiction outweighs the stigma attached to heroin use. Additionally, it is far easier to pay $10 for a dose of heroin than $80 for an oxycodone tablet," Goodlatte said.

"Focusing on the prescription drug problem is a top priority," Botticelli said. He suggested that doctors be required to complete continuing education on opioid drugs, to learn their connection and effects on heroin use.

"We are dealing with a public healthcare crisis driven by a strong demand for opioid drugs," said Rep. Judy Chu, D-Calif.

Mexican cartels, trafficking in the U.S., are taking advantage of the connection between painkillers and heroin, Riley told lawmakers. He said the cartels have "seen the spread of prescription drug use, and they know at some point that availability does cease."

More than half of the heroin in the U.S. has been smuggled across the Southwest border by Mexican cartels, Riley said.

"The DEA is addressing this evolving threat by targeting the highest-level traffickers and the vicious organizations they run," Riley said.

Lawmakers in both chambers of Congress have offered multiple bills this session aimed at curbing drug trafficking and rampant opioid use, but none has passed.