MANCHESTER, N.H. (Reuters) - President Donald Trump , targeting the U.S. opioid epidemic, called again on Monday for the execution of drug dealers, a proposal that so far has gained little support in Congress, amid criticism from some drug abuse and criminal justice experts.

At an event in Manchester, New Hampshire, Trump unveiled an anti-opioid abuse plan, including his death penalty recommendation and one for tougher sentencing laws for drug dealers.

For Trump, the visit to New Hampshire returns him to a state that gave him a key Republican primary election win when he was a political newcomer in 2016. Back then, he promised to tackle the opioid crisis, which is particularly severe in the New England state.

Since then, he has taken only modest steps. He declared the opioid crisis a public health emergency in October, but without providing more money to fight the epidemic.

Some critics, including Democratic lawmakers, said then that the declaration was meaningless without additional funds.

Addiction to opioids - primarily prescription painkillers, heroin and fentanyl - is a growing problem in the United States, especially in rural areas. According to the U.S. Centers for Disease Control and Prevention, 42,000 people died from opioid overdoses in 2016.

The new White House plan will seek to cut opioid prescriptions by a third over the next three years by changing federal healthcare programs, the White House officials said.

The White House did not offer examples of when it would be appropriate to seek the death penalty for drug dealers and referred further questions to the Justice Department.

The Justice Department said it will have a statement around the time of Trumps afternoon event in New Hampshire.

Dr Harold Pollack, an urban public health professor at the University of Chicago, said, I dont think the death penalty for drug dealers will accomplish very much.

He said there was little evidence that tougher sentencing reduced the availability of street drugs.

Pollack urged Trump to work with Republican state governors to expand the Medicaid federal health program so that drug addicts could get more access to healthcare and counseling.

David Safavian, deputy director for the American Conservative Union Foundations Center for Criminal Justice Reform, said Trumps plan had some good parts, including focusing on addiction as a way to lower crime rates.

Like any plan, there are some areas where the details matter, he said. For example, identifying those reporting to prison with addiction issues is an important first step.

It was also important to ensure the Bureau of Prisons had sufficient resources to treat addicted inmates so they could avoid a cycle of abuse and incarceration, he said.

Kevin Ring, president of Families against Mandatory Minimums, which campaigns against sentencing they see as overly harsh, said Trumps plan calling for stiffer sentences or seeking thedeath penalty against drug dealers, was merely doubling down on a failed strategy.

(Additional reporting by Steve Holland, Ayesha Rascoe and Sarah N. Lynch; Editing by Kevin Drawbaugh and Rosalba OBrien)