The former U.S. ambassador to Russia says he has been banned from traveling there in a tit-for-tat response to U.S. visa bans for senior Russian officials.

Michael McFaul told The Associated Press on Friday that he had applied for a Russian visa in order to travel to Moscow in December for possible work on ensuring a smooth transition to a Hillary Clinton presidency, had she been elected.

McFaul, who served in Moscow from 2012 to 2014 and now works at Stanford University, said he was "extremely disappointed" by the decision. He added that he has traveled to Russia hundreds of times, has many friends there and has spent most of his career studying Russia.

The Russian Foreign Ministry confirmed the ban, Russian news agencies reported, citing unidentified sources.