The attorney general then had lunch with Pat A. Cipollone, the White House counsel and a longtime friend and colleague, in what officials said was a previously scheduled get-together. While Mr. Barr has been incredibly frustrated and has a limit to what he will put up with, people who know him said they doubted he would give in so quickly.

An abrupt departure by Mr. Barr would roil a Justice Department on track to deliver several initiatives important to Mr. Trump, including an overhaul of the F.B.I., a criminal investigation into the origins of the Russia inquiry and a continuing leak investigation into James B. Comey, the former director of the F.B.I. It would also leave the president with a vacancy at the top of the Justice Department that might be hard to fill eight months before the election.

Mr. Barr has taken heat from critics both inside and outside his department over what they see as the politicization of the law enforcement system. More than 1,100 former Justice Department officials called for Mr. Barr’s resignation, and a group representing the nation’s federal judges scheduled an emergency telephone conference to address the president’s attacks on one of their own.

The Justice Department dismissed suggestions on Tuesday night that Mr. Barr’s departure was imminent. “Addressing Beltway rumors: The Attorney General has no plans to resign,” Kerri Kupec, the department spokeswoman, wrote on Twitter. Stephanie Grisham, the White House press secretary, retweeted Ms. Kupec’s message.

The president told reporters on Tuesday that Mr. Stone, a longtime friend and off-and-on adviser, and Mr. Flynn, a campaign adviser before serving briefly as his national security adviser, were both “treated very unfairly.” He called Mr. Stone’s conviction “a very, very rough thing” and said that Mr. Flynn’s “life has been destroyed.”

Mr. Stone, who was convicted in November of seven felonies for obstructing a congressional inquiry into the Trump campaign’s ties to WikiLeaks, which disseminated Democratic emails stolen by Russian agents, is scheduled to be sentenced on Thursday. Mr. Flynn pleaded guilty to lying to the F.B.I. about his dealings with Russian officials but wants to withdraw his plea.

Asked whether he was considering pardons for Mr. Stone, Mr. Flynn or Paul Manafort, his former campaign chairman convicted on tax and other financial fraud charges, Mr. Trump said, “I’m not even thinking about that.” But aides said he had broached the idea and critics said Tuesday’s pardons and commutations for convicted political figures like Rod R. Blagojevich and Bernard B. Kerik sent a clear message to the president’s associates that he may yet clear them.