Story highlights He's been at the center of a firestorm over contacts with Trump team

Kislyak's replacement as ambassador is Anatoly Antonov

(CNN) The Russian Ambassador to the US at the center of a political firestorm over his encounters with associates of President Donald Trump is leaving his post, but Russia says the move is not unexpected.

Russian Foreign Ministry spokeswoman Maria Zakharova is clarifying reports that Russian Ambassador Sergey Kislyak is leaving his post in Washington and returning to Moscow.

"The changing of an ambassador, especially to a major country, is a question of at least a year. It is all planned in advance. Especially when an ambassador has worked for a long time. No unplanned replacement of Russian ambassadors is taking place," she told CNN.

Kislyak's replacement as ambassador, Anatoly Antonov, was approved last month by the foreign affairs committee of the lower house of the Russian parliament, according to state media.

The 66-year-old came under the spotlight when his communications with Trump's short-lived National Security Adviser Michael Flynn led to Flynn being fired for failing to be entirely up front about them.