WASHINGTON (AP) — President Donald Trump's former nominee to be the nation's drug czar is defending his role in writing a law that critics say weakened the government's authority to stop companies from distributing opioids.

Rep. Tom Marino, R-Pa., said he's proud of his work on the 2016 law, which passed without opposition in the House and Senate and was signed by President Barack Obama.

In a statement released by his office, Marino said the law will help "facilitate a balanced solution" by ensuring access to certain medications while allowing the Drug Enforcement Administration to prevent the sale and abuse of prescription drugs.

The former prosecutor withdrew Tuesday as Trump's nominee to head the White House Office of National Drug Control Policy following reports by The Washington Post and CBS News about the law. Critics say the measure has undermined efforts to restrict the flow of pain pills that have led to tens of thousands of deaths.

Marino disputed that, saying he wanted to "insist on correcting the record regarding the false accusations and unfair reporting to which I have been subjected."

The Post reported Sunday that for years, some drug distributors were fined for repeatedly ignoring DEA warnings to shut down suspicious sales of hundreds of millions of pills, while the companies racked up billions of dollars in sales.

The new law makes it virtually impossible for the DEA to freeze suspicious narcotic shipments from the companies, according to the report. It cited internal DEA and Justice Department documents and an independent assessment by the DEA's chief administrative law judge.

Before the law was changed, the DEA was able to immediately prevent drugs from reaching the street based on its judgment that the drugs posed an "imminent danger" to a community. Now, the agency must demonstrate that a company's actions represent "a substantial likelihood of an immediate threat," a much higher bar that officials say is difficult to meet.

Trump is under growing pressure to fulfill his pledge to declare the opioid epidemic a "national emergency," as a commission he's convened on the subject has urged him to do. Trump told reporters Monday that he will make the declaration official next week.

Trump told Fox News Radio on Tuesday that Marino "felt compelled" to step down from the job. "He feels very strongly about the opioid problem and the drug problem, and Tom Marino said, 'Look, I'll take a pass,'" Trump said.

Democrats hailed Marino's withdrawal.

"We need a drug czar who has seen these devastating effects and who is passionate about ending this opioid epidemic," said Sen. Joe Manchin, D-W.Va., whose state has been ravaged by the drug crisis, which kills an estimated 142 people a day nationwide.

The Post reported that the drug industry worked behind the scenes with lobbyists and key members of Congress, including Marino, pouring more than a million dollars into their election campaigns.

New Jersey Gov. Chris Christie, who heads the White House commission on opioids, said it was "pretty extraordinary" that Congress approved the drug law without a roll-call vote.

It "looks to me like the fix was in when you have something like that," Christie said at a news conference Wednesday, adding that Marino's withdrawal "raises the stakes" for the president and Congress to do more on opioids.

"It's about not just picking a new drug czar, because to me that's just a small part of it. This is about changing the attitude of the American people and its leaders towards these drugs," Christie said. "Eighty-five percent of all the opioids consumed in the world are consumed in the United States. It's just wrong, and we need to give all our law enforcement agencies every tool they need to be able to help interdict and prevent people's addiction."