The state of alert comes on the heels of Russian President Vladimir Putin's order to partially mobilize Russian men to fight in his war in Ukraine.

The U.S. Embassy in Moscow issued a nightly security alert urging U.S. citizens to leave Russia immediately as there are still options to leave the country.

The alert follows Russian President Vladimir Putin's order to partially mobilize Russian men to fight in his war in Ukraine.

"Russia may refuse to recognize dual nationals, deny them access to assistance in U.S. consulates, prevent them from leaving Russia, and may recruit dual nationals for military service," the warning said. "Russian authorities have arrested US citizens who participated in demonstrations," the warning added.

The U.S. Embassy has consistently warned against traveling to Russia and leaving the country immediately.

The embassy alert urged U.S. citizens to "avoid all political or social protests, and not to photograph security personnel in these events," noting that "the rights to peaceful assembly and freedom of expression are not guaranteed in Russia."

The warning said the embassy "has severe restrictions on its ability to assist U.S. citizens, and circumstances, including transportation options, may suddenly become limited."