WASHINGTON — President-elect Donald J. Trump said in an interview broadcast on Sunday that he did not believe American intelligence assessments that Russia had intervened to help his candidacy, casting blame for the reports on Democrats, who he said were embarrassed about losing to him.

“I think it’s ridiculous. I think it’s just another excuse,” Mr. Trump said in the interview, on “Fox News Sunday.” “I don’t believe it.”

He also indicated that as president, he would not take the daily intelligence briefing that President Obama and his predecessors have received. Mr. Trump, who has received the briefing sparingly as president-elect, said that it was often repetitive and that he would take it “when I need it.” He said his vice president, Mike Pence, would receive the daily briefing.

“You know, I’m, like, a smart person,” he said. “I don’t have to be told the same thing in the same words every single day for the next eight years.”