The radioactive political fallout from Donald Trump’s decision to fire James Comey, leading to the appointment of Robert Mueller, appears not to have dissuaded the president from continuing to meddle in an investigation that could very well turn on obstruction of justice. In recent months, Trump’s legal team has managed, to a degree, to curtail his public remarks on the matter, but behind closed doors, the president has reportedly urged multiple Republican lawmakers to exert their influence to end the probe.

More than a half dozen elected G.O.P. officials and Republican aides say Trump pressed powerful members of his party to hasten conclusions in the ongoing congressional investigation into Russian interference in the 2016 election, The New York Times reported late Thursday. The overtures, which were made over the summer, represent an exceptional level of intervention by a sitting president over the legislative branch.

White House spokesman Raj Shah dismissed the idea that the president acted improperly, telling the Times that Trump “at no point has attempted to apply undue influence on committee members.” But at least one Republican lawmaker notably went on the record to describe, in chilling terms, the extent of the president’s pressure campaign. “It was something along the lines of, ‘I hope you can conclude this as quickly as possible,’” said Senator Richard Burr, who as chairman of the Senate Intelligence Committee wields great influence over his panel’s investigation. Burr reportedly told Trump that “when we have exhausted everybody we need to talk to, we will finish.” One Republican close to Burr described Trump’s request as “very forceful.” And Trump also lobbied for other Republicans to turn up the heat on Burr, according to sources who spoke with the Times.

The North Carolina Republican told the outlet that he chalked the remarks up to the president being a political neophyte, but conceded that Trump similarly petitioned other G.O.P. members of the committee, who “promptly shared any conversations that they’ve had.” According to an official familiar with the matter, the president implored Missouri Senator Roy Blunt “to wrap up this investigation” during a flight on Air Force One in August. Trump also expressed his frustrations about the enduring inquiries to Mitch McConnell, reportedly criticizing the Senate majority leader along with Bob Corker, the chairman of the Senate Foreign Relations Committee, for not doing more to protect him and his associates from scrutiny over his campaign’s ties to Russia. When Senator Thom Tillis introduced legislation seeking to shield Mueller from being fired, he received a call from the president, the Times reported. (He characterized the conversation as “pleasant” and said Trump “just asked me where my head was.”) With at least one senator, the president took a different tack, suggesting that the lawmaker dig into Hillary Clinton’s ties to Fusion GPS, the political intelligence firm that commissioned the infamous Trump-Russia dossier.

Senator Dianne Feinstein, the ranking Democrat on the Senate Judiciary Committee, derided Trump’s campaign to bring the congressional inquiries to an end. “It is pressure that should never be brought to bear by an official when the legislative branch is in the process of an investigation,” the California lawmaker told the Times.

It is also, potentially, a stunningly short-sighted decision, given the trouble Trump’s interventions have brought him in the past. His reported request to “conclude this as quickly as possible” recalls the appeal Comey said he himself received shortly before he was fired. “He is a good guy and has been through a lot,” Comey testified Trump said of Michael Flynn, urging him to stop investigating him. “He then said, ’I hope you can see your way clear to letting this go, to letting Flynn go. He is a good guy. I hope you can let this go.’” When Comey didn’t, Trump engineered his ouster and was rewarded with Mueller in his place. On Friday morning, news broke that after meeting with Mueller, Flynn would plead guilty to lying to the F.B.I., but would not be charged with any other crimes. The move has been widely interpreted as suggesting that Trump’s former right-hand man has cut a deal.