U.S. Labor Secretary Alexander Acosta prepares to testify before the House Ways and Means Committee April 17, 2018 in Washington, DC.

President Donald Trump's Labor secretary, Alex Acosta, defended a 2007 deal with accused sex trafficker Jeffrey Epstein on Tuesday amid renewed scrutiny over his actions in the case.

"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, who was U.S. attorney in Miami at the time of the deal, wrote on Twitter.

"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," he wrote.

Acosta tweet

Acosta's comments come amid a flurry of demands from Democrats for his resignation, including from the two top Democrats in Congress.

New York prosecutors charged Epstein with trafficking dozens of underage girls on his properties in New York and Florida in an indictment unsealed Monday. He has pleaded not guilty and was ordered held without bail.

Acosta, who led the prosecution of Epstein for related crimes more than a decade ago, ultimately decided to bring no federal charges. Acosta did not disclose the deal to Epstein's alleged victims, in violation of the law, a judge ruled earlier this year. Epstein ultimately spent 13 months in jail, most of which was on work release.

Acosta's role in the deal was recently detailed by an investigative report in The Miami Herald, which characterized the non-prosecution agreement Epstein received as "the deal of a lifetime."

Senate Minority Leader Chuck Schumer of New York said on the floor of the Senate on Tuesday that it was "now impossible for anyone to have confidence in Secretary Acosta's ability to lead the Department of Labor. If he refuses to resign, President Trump should fire him."

The Department of Labor oversees federal programs that combat human trafficking.

Trump appears unlikely to seek Acosta's resignation or to fire him. The president told reporters on Tuesday that he felt badly for Acosta, and noted that a lot of people were involved in the decision not to prosecute him on federal charges.

"What I do know is that he's been a great, really great secretary of Labor. The rest of it, we'll have to look at. We'll have to look at it very carefully," Trump said.