President Donald Trump’s point man in the quest to reduce drug prices for American consumers clashed Tuesday with a disbelieving senator, who said the White House’s blueprint for battling Big Pharma is bogus.

The face-off between Health Secretary Alex Azar and Sen. Elizabeth Warren, D-Mass., took place at a hearing before the Senate Committee on Health, Education, Labor and Pensions on Trump’s proposed drug-pricing plan.

“You and President Trump say that you want to get tough on drug companies,” Warren said. “On May 30, the president said that in reaction to the release of the drug-pricing blueprint, drug companies would be ‘announcing voluntary massive drops in prices within two weeks.' "

Warren said that when she and another senator asked the nation’s top 10 drug makers whether they intended to drop prices in response to Trump’s blueprint, “zero out of 10 gave any indication that they planned to do so.”

"He said there would be massive decreases in prices within two weeks," Warren said. "It's been two weeks and there have been no decreases and an indication of increase."

Azar insisted that several drug companies “are looking at substantial and material decreases of drug prices.”

“Can you guarantee that no Medicare beneficiary will pay higher drug prices as a result of your plan to change coverage under Medicare?” Warren asked.

Azar avoided giving a direct answer, saying only, “We are going to work on it.”

“I’ve asked the question now three times and you’ve given me no answer at all,” Warren said. “You cannot guarantee that there will not be Medicare beneficiaries who will be paying more.”

Medicare is the age-based federal health insurance program that guarantees coverage for individuals aged 65 and over. About 60 million people are signed up for the Medicare prescription drug benefit, which accounts for nearly a third of all spending on prescription drugs in the U.S.

While running for president, Trump broke with Republicans and embraced a longstanding Democratic proposal to allow the federal government to negotiate lower drug prices for Medicare recipients.

But in May he released a plan called American Patients First that he claimed would give Medicare "new tools to negotiate lower prices" — but does not allow Medicare to barter directly with drug companies to lower prescription prices.

Democrats quickly accused Trump of backtracking on a campaign promise.