HARTFORD, Conn. — Connecticut U.S. Sen. Richard Blumenthal said Friday that the Justice Department's threat against him over his investigation of donors to President Donald Trump's White House ballroom is "a blatant abuse of prosecutorial power," and he vowed to keep digging.

"I just want to make absolutely clear that the Department of Justice threatening me and other colleagues will in no way deter or discourage me from continuing investigation into corruption surrounding the donations made to Trump's East Wing Ballroom boondoggle," Blumenthal said.

His remarks came two days after U.S. Attorney Aaron Reitz of the Southern District of Texas posted a letter ordering Blumenthal to preserve all records from his ballroom inquiry and accusing him of using congressional oversight to intimidate donors, The Signal reported Thursday. The letter did not announce any charges or allege that Blumenthal had committed a crime. It gave him until 6 p.m. Nov. 18 to confirm he had preserved the materials.

On Friday, Blumenthal said the threat "is designed to enable concealment of those potential pay-to-play schemes."

"This weaponization of the Department of Justice for political purposes is absolutely abhorrent, not just as to me, but as to others that it is trying to discourage from pursuing proper action," he said. "Donald Trump, in fact, is using the Department of Justice as a political weapon, not as a legitimate investigative or prosecutorial agency."

"I am determined that I will not be intimidated," Blumenthal said. "I will not be deterred."

Nvidia's donation

Blumenthal, the incoming chair of the Senate Permanent Subcommittee on Investigations, pointed to chipmaker Nvidia's $25 million donation to the ballroom, saying "the full range of potential corruption here involving pay-to-play has to be a target for congressional investigation."

"We have at least circumstantial evidence," he said. "Fourteen corporations, for example, have received new or expanded contracts after their donation to the ballroom boondoggle."

He said Nvidia is one of them, and that its donation "may have impacted the Trump administration's policies toward export controls as well as other kinds of actions that benefited NVIDIA."

Blumenthal also accused the secretary of commerce of having "evidently helped to enable transfers of high-powered chips from NVIDIA to China in violation of potential laws," saying the transfers endangered national security and U.S. economic competitiveness. He did not detail the evidence for the claim on Friday.

"Corruption has costs," he said.

Nvidia's $25 million gift, among the largest to the project, was revealed in an internal fundraising spreadsheet obtained by The Washington Post. The donation came about three months after the company reached a deal with the Trump administration to sell advanced chips to China, according to reporting on the list.

Nvidia has said it was proud to give to a nonpartisan trust. "As an American company, our support for the United States is paramount, and independent of any business interests," a company spokesperson said, according to the Associated Press.