WASHINGTON — For months, President Trump and his aides have insisted that they had no contact with Russian officials during the presidential campaign, a denial Mr. Trump repeated last week.

“I have nothing to do with Russia,” he told reporters on Thursday. “To the best of my knowledge, no person that I deal with does.”

The denial stands at odds with statements by Russian officials, who have at least twice acknowledged contacts with aides to Mr. Trump before the election.

It is not uncommon for a presidential campaign to speak to foreign officials, which makes the dispute particularly unusual. At the same time, any contacts would have taken place during a period when American intelligence agencies believe the Russian government was trying to disrupt the election with a campaign of computer hacking.