U.S. adversaries are preparing to stoke uncertainty about the validity of the Nov. 5 presidential election results after polls close, anticipating a contested vote, a senior U.S. intelligence official said on Monday.

In a briefing to reporters on the election influence activities of Russia, China, Iran and Cuba, U.S. intelligence officials said "foreign influence actors" would likely work to sow doubt about the results. Russia and Iran have already sought to sway U.S. voters during this year's presidential campaign while China has sought to influence several down-ballot races, including congressional campaigns, according to U.S. intelligence agencies. Foreign actors would likely seek to use the uncertainty of a contested election to undermine trust in the integrity of the election and election processes and exacerbate divisions among Americans, according to the U.S. intelligence official.

Russia sought to encourage the U.S. public to oppose pro-Ukrainian policies, while actors linked to China's government were focused on "tens" of down-ballot races.