The department told the dependents of staffers at the US Embassy in Kyiv that they must leave the country.
It also said that non-essential embassy staff could leave Ukraine at government expense.
The move came amid rising tensions about Russia’s military build-up on the Ukraine border that were not eased during talks on Friday between Secretary of State Antony Blinken and Russian Foreign Minister Sergey Lavrov in Geneva.
State Department officials stressed the Kyiv embassy will remain open and that the announcement does not constitute an evacuation.
The move had been under consideration for some time and does not reflect an easing of US support for Ukraine, the officials said.
In a statement, the State Department noted recent reports that Russia was planning significant military action against Ukraine.
However, the Russian Foreign Ministry has accused Nato countries of escalating tensions around Ukraine with disinformation.
The State Department added: “The security conditions, particularly along Ukraine’s borders, in Russia-occupied Crimea, and in Russia-controlled eastern Ukraine, are unpredictable and can deteriorate with little notice.
“Demonstrations, which have turned violent at times, regularly occur throughout Ukraine, including in Kyiv”.