Labor Secretary Alex Acosta on Tuesday defended his role in securing a plea deal for politically connected sex offender Jeffrey Epstein more than a decade ago, while a flood of top Democrats demanded he resign for helping to orchestrate what Senate Minority Leader Chuck Schumer slammed as a "sweetheart deal."

"If he refuses to resign, President Trump should fire him," Schumer, D-N.Y., said on the Senate floor Tuesday.

House Speaker Nancy Pelosi demanded Acosta step down, tweeting Monday night, "As US Attorney, he engaged in an unconscionable agreement w/Jeffrey Epstein kept secret from courageous, young victims preventing them from seeking justice. This was known by @POTUS when he appointed him to the cabinet."

Acosta took to Twitter to defend his handling of the notorious case, and to praise federal prosecutors in New York for charging the financier Monday with sex trafficking dozens of young girls — some as young as 14 — during the early 2000s.

"The crimes committed by Epstein are horrific, and I am pleased that NY prosecutors are moving forward with a case based on new evidence," Acosta wrote in a series of tweets.

"With the evidence available more than a decade ago, federal prosecutors insisted that Epstein go to jail, register as a sex offender and put the world on notice that he was a sexual predator. Now that new evidence and additional testimony is available, the NY prosecution offers an important opportunity to more fully bring him to justice."

The crimes committed by Epstein are horrific, and I am pleased that NY prosecutors are moving forward with a case based on new evidence. — Secretary Acosta (@SecretaryAcosta) July 9, 2019

Acosta's comments came after Schumer, Pelosi and numerous Democratic presidential candidates called on him to resign for his role in securing the federal non-prosecution agreement against Epstein in Florida in 2008. Acosta maintains the arrangement helped pressure Epstein into pleading guilty to state charges and having to register as a sex offender.

"Since when do underage girl sex ring traffickers get to go to their office every day while they serve their time?" Sen. Amy Klobuchar of Minnesota, a 2020 candidate, tweeted Tuesday. "I didn't vote for former Florida U.S. Attorney Acosta to begin with and he should step down."

Sen. Kirsten Gillibrand of New York, another presidential candidate who voted against Acosta's nomination in 2017, told reporters after a campaign event in New Hampshire that Acosta "never should have been there in the first place." Sen. Kamala Harris of California tweeted, "We need leaders committed to fighting for justice for survivors of abuse, not protecting predators."

Front-runner and former Vice President Joe Biden tweeted that Acosta should step down immediately.

"The abuse of a child is one of the most heinous, despicable abuses of power imaginable. It is inexcusably poor judgment for a US Attorney to seek leniency for someone guilty of it. Secretary Acosta should provide his resignation immediately," Biden said.

All of the Democratic senators who voted to confirm Acosta in 2017 and who are still in office — Mark Warner of Virginia, Bob Menendez of New Jersey, Joe Manchin of West Virginia, Jon Tester of Montana and Catherine Cortez Masto of Nevada — all told NBC News Acosta should go, with some citing "new information." Acosta's role in the plea agreement has been public knowledge for years, and he was asked about how he handled it during his confirmation hearing.

Acosta was the U.S. attorney for the Southern District of Florida at the time of the original Epstein criminal case. His office reached the secret non-prosecution deal in 2008 with the wealthy financier to halt the federal sex abuse investigation involving dozens of teenage girls in return for him pleading guilty to lower state charges involving a single victim.

Epstein pleaded guilty to procuring a person under 18 for prostitution and felony solicitation of prostitution, which required him to register as a sex offender and serve about a year in county jail. He was able to leave almost daily for work, and was allowed to have his own private security detail behind bars.

Had the feds prosecuted him, he could have faced a potential life sentence in federal lockup if convicted.

Acosta had been actively involved in the plea negotiations, according to documents that were introduced into evidence in a lawsuit by two victims who said their rights were violated. That included an email between Acosta and one of Epstein's lawyers, former Whitewater special prosecutor Ken Starr, in which he agreed to temporarily hold off on sending out victim notification letters at Starr's request.

The non-prosecution agreement also protected the alleged co-conspirators who helped recruit the girls, and contained a provision ensuring the deal "will not be made part of any public record."

Acosta's office said he is not considering stepping down. Trump praised him as "an excellent Secretary of Labor" at the White House on Tuesday. "The rest of it we'll have to look at," he told reporters.

Senior adviser Kellyanne Conway told reporters Tuesday the focus should be on Epstein, and not on Acosta.

"I hope we're all paying attention to who the true perpetrator is here," she said.

Epstein, 66, was arrested over the weekend and charged in the Southern District of New York with sex trafficking dozens of girls as young as 14 in New York and Florida during the same time period as the earlier Florida probe. The 2008 agreement with Acosta's office did not protect Epstein from being prosecuted for alleged crimes in parts of the country other than South Florida, and prosecutors in New York say their case involves new victims and new evidence, including a cache of incriminating pictures that were found in a vault in Epstein's Manhattan mansion.

Epstein has pleaded not guilty. If convicted, he faces up to 45 years in prison.

The victims had been challenging his non-prosecution agreement in Florida. In February, a federal judge ruled that the prosecutors led by Acosta had violated federal law by failing to notify the accusers of the agreement.

But the Justice Department filed court papers last month that contend Epstein's plea deal cannot be legally challenged because he has complied with its terms. The accusers have until Monday to respond to the federal filing.

Earlier this year, then-White House press secretary Sarah Sanders said the administration was "looking into" Acosta's role in the 2008 agreement.

Epstein's political connections include President Donald Trump and former President Bill Clinton.

In a statement Monday, Clinton — who flew on one of Epstein's planes several times, according to flight records reviewed by NBC News — denied knowing anything of the crimes Epstein pleaded guilty to years ago and the ones which he was charged with this week.

In 2002, Trump told New York magazine that he'd known Epstein "for 15 years," calling him a "terrific guy."

"He's a lot of fun to be with," Trump said. "It is even said that he likes beautiful women as much as I do, and many of them are on the younger side. No doubt about it — Jeffrey enjoys his social life."

On Tuesday, Trump told reporters "he's not a fan" of Epstein's. “I had a falling out with him a long time ago,” Trump said. “I don’t think I’ve spoken to him for 15 years.”