LAS VEGAS — President Trump said Friday that the disclosure by American intelligence officials that Russia was again meddling in a presidential election in his favor was merely another partisan attack against him, continuing a pattern in which he has sought to dismiss warnings of foreign interference in American elections.
“Another misinformation campaign is being launched by Democrats in Congress saying that Russia prefers me to any of the Do Nothing Democrat candidates who still have been unable to, after two weeks, count their votes in Iowa,” Mr. Trump wrote on Twitter. “Hoax number 7!”
Mr. Trump was responding to reports of a classified briefing in which intelligence officials told members of the House Intelligence Committee that Russia was interfering in the 2020 presidential campaign to aid his re-election. Republicans on the committee challenged the conclusions and Mr. Trump berated Joseph Maguire, the outgoing acting director of national intelligence, for allowing the briefing to happen.
Intelligence officials have also concluded that the Russians are seeking to help Senator Bernie Sanders of Vermont in the Democratic presidential primaries.
At an afternoon campaign rally, Mr. Trump continued with his accusations that Democrats were behind the reports and said they were trying to “poison our democracy” and circulating “vile” hoaxes.
“I was told a week ago,” Mr. Trump said. “They said, ‘you know they’re trying to start a rumor.’ It’s disinformation. That’s the only thing they’re good at. They’re not good at anything else. They get nothing done. Do nothing Democrats.”
On the final event in a four-day swing through the West, Mr. Trump suggested that President Vladimir V. Putin of Russia, would prefer Mr. Sanders.
Mr. Trump, who has been cheerful in public and private about his re-election prospects, used the trip to raise millions from high-dollar donors and charm his political base at rallies in three states. And by returning every night to Las Vegas and holding his final rally there, he also tried to divert attention from Saturday’s Democratic caucuses in Nevada.
Mr. Trump has visited every state that has held a primary or caucus so far this year, making trolling Democratic candidates a cornerstone of his campaign strategy.
At his rally on Friday, the president called up members of the 1980 “Miracle on Ice” men’s hockey team to take the stage behind him and waxed at length about his reality show “The Apprentice.”
“Speaking also of reality television: This is the greatest show of all time, huh?” the president said. “I have to get back to Washington and work. I feel guilty. This is too much fun.”
Mr. Trump spoke for nearly two hours and fired the crowd up with a litany of claims about his accomplishments during his first three years in office, many of them exaggerated or misleading.
During an extended discussion about the dangers of illegal immigration, Mr. Trump noted that “illegal crossings are down 75 percent from last spring.” He did not mention that the decrease followed a huge surge in border apprehensions on his watch, leaving the number about where it was when he took office.
Aside from appearing unbound and ebullient on the campaign trail, Mr. Trump also used the trip as an opportunity to take on some favorite targets, casting doubt on assorted institutions at every turn.
He voiced his suspicions about Saturday’s Nevada caucuses, comparing it to the disastrous ones held in Iowa earlier this month.
“I hear their computers are all messed up just like they were in Iowa,” he said.
The president described members of the media as “the most dishonest human beings in the world” and accused law enforcement of harboring “dirty cops.”
He also repeatedly joked with the crowd that he would stay president longer than two terms, a comment he has made at other events.
Mr. Trump has a long history of dismissing the assessments made by intelligence agencies that he has deemed unfair or unflattering.
Multiple agencies have determined that Russia meddled in the 2016 election, and, before the 2018 midterms, delivered warnings that Russia was prepared to do it again. Early in his presidency, Mr. Trump grudgingly accepted those assessments before falling back on personal assurances from Mr. Putin.
“He said he didn’t meddle,” Mr. Trump said in November 2017. “I asked him again. You can only ask so many times. Every time he sees me, he says, ‘I didn’t do that.’ And I believe, I really believe, that when he tells me that, he means it.”
Since then, Mr. Trump, with the assistance of his Justice Department, has moved to retaliate against the intelligence community rather than Mr. Putin. A federal prosecutor is scrutinizing how intelligence officials assessed Russia’s 2016 election interference, targeting the former C.I.A. director John O. Brennan in particular.
Mr. Trump’s anger at the intelligence assessment delivered on Feb. 13 to lawmakers was magnified by the presence at the briefing of Representative Adam B. Schiff, Democrat of California, who is the chairman of the Intelligence Committee and played a lead role in the impeachment proceedings against Mr. Trump.
The president’s decision to remove Mr. Maguire and install Richard Grenell, the ambassador to Germany and a fervent loyalist, was also seen as a direct outcome of the briefing.
On Thursday evening, Mr. Trump told reporters aboard Air Force One that Representative Doug Collins of Georgia, an ally and a vocal opponent of impeachment, was one of the candidates under consideration as a permanent successor. By Friday morning, Mr. Collins said he was not interested.
“This is not a job that interests me; at this time, it’s not one that I would accept because I’m running a Senate race down here in Georgia,” Mr. Collins said in an interview on Fox News. Mr. Trump then wrote on Twitter that he had a list of four candidates to succeed Mr. Grenell, and that he would make his decision in the coming weeks.
Michael D. Shear contributed reporting from Washington.