President Donald Trump's pick for US drug czar withdrew today after it become public that he spearheaded a bill that undercut the government's power to crack down on opioid makers that were flooding the market with the addictive painkillers.

Trump had pegged Tom Marino, a Republican congressman from Pennsylvania, to lead the Office of National Drug Control Policy, a post that required Senate confirmation.

Trump wrote on Twitter: "Rep. Tom Marino has informed me that he is withdrawing his name from consideration as drug czar. Tom is a fine man and a great Congressman!"

A spokeswoman for Marino's office said the congressman had no immediate comment.

The Washington Post and the CBS program "60 Minutes" published an investigation on Sunday that showed that Marino had worked to weaken federal efforts to slow the flow of opioid drugs.

The legislation championed by Marino, which was passed by Congress and signed into law last year by Democratic President Barack Obama, was the product of a drug industry quest to weaken the US Drug Enforcement Administration's authority to stem the flow of painkillers to the black market.

The law made it almost impossible for the DEA to freeze suspicious shipments of narcotics to prevent them from reaching the street, according to government documents cited by the Post.

According to the US Centers for Disease Control and Prevention, opioids were responsible for more than 33,000 US deaths in 2015, the latest year for which data is available. Estimates show the death rate has continued rising.

Senate Minority Leader Chuck Schumer called Marino's withdrawal "the right decision," but added that "the fact that he was nominated in the first place is further evidence that when it comes to the opioid crisis, the Trump administration talks the talk, but refuses to walk the walk."