The White House is refusing requests from two key House Democrats to produce records related to concerns about potential political interference by President Donald Trump in the government’s decision to sue to block AT&T Inc.’s US$85 billion acquisition of Time Warner.

The refusal is the latest escalation of tensions between the Trump administration, which unsuccessfully opposed the combination in court, and House Judiciary Committee Chairman Jerrold Nadler over the disclosure of information to Congress.

White House Counsel Pat Cipollone said in a letter Monday to Nadler and Representative David Cicilline that the request for records related to discussions by Trump and his advisers about the merger were “at the very core of the executive branch’s confidentiality interests” which protect the president’s ability to get candid advice from aides. In the letter, which was obtained Bloomberg, Cipollone said he understood that the Justice Department would respond to inquiries on the topic “in due course.”

The New Yorker reported in March that Trump, who routinely criticizes Time Warner’s CNN news channel, wanted then-economic aide Gary Cohn to push the Justice Department to sue to block the merger. Cohn resisted the request, the New Yorker reported. The Justice Department eventually did sue to block the merger, denying that the decision was politically motivated or that there was interference from the White House. AT&T prevailed in February when the judge overseeing the case said the government had failed to prove the combination was anticompetitive and allowed the companies to merge.

Cipillone also wrote in his letter that “the president has an important role in the antitrust area” because of his constitutional duty to ensure the faithful execution of laws.

In a statement on Tuesday, Nadler and Cicilline said Cipollone “has made a blanket claim that all White House communications -- regardless of whether they contain evidence of improper or even unlawful activities -- are protected by a cone of secrecy.”

“It appears the White House Counsel believes that the President has unfettered discretion to use law enforcement as a political weapon,” the two lawmakers said, which they called “incompatible with our democracy.”

Nadler and Cicilline said that they would “pursue this matter.” Cicilline, who chairs an antitrust subcommittee of the judiciary panel and joined Nadler’s earlier requests, said in March that Congress may issue a subpoena in the probe if they are “compelled to.”