From the U.S. State Department (emphasis theirs):

Do not travel to Russia due to the unprovoked and unjustified attack by Russian military forces in Ukraine, the potential for harassment against U.S. citizens by Russian government security officials, the Embassy's limited ability to assist U.S. citizens in Russia, COVID-19 and related entry restrictions, terrorism, limited flights into and out of Russia, and the arbitrary enforcement of local law. U.S. citizens should depart Russia immediately.

U.S. citizens residing or traveling in Russia should depart immediately. Limited commercial flight options are still available. Overland routes by car and bus are also still open. If you wish to depart Russia, you should make arrangements on your own as soon as possible. If you plan to stay in Russia, understand the U.S. Embassy has severe limitations on its ability to assist U.S. citizens, and conditions, including transportation options, may change suddenly. U.S. citizens who are able to depart Russia for another country and are in need of emergency assistance upon arrival may contact a U.S. embassy or consulate in that country.

This is a step-up from the State Department's previous guidance saying that Americans in Russia should "consider" leaving.

From Fox News:

If you're American, get the heck out of Russia.

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