Biden administration considering options for possibly evacuating US citizens from Ukraine if Russia invades

The Biden administration is exploring options for a potential evacuation of US citizens from Ukraine if Russia were to invade the country and create a dire security situation, half a dozen sources tell CNN.

The contingency planning is being led by the Pentagon, the sources said, and comes as the administration briefs Congress on how the US is preparing. In a "gloomy" briefing to senators by senior State Department official Victoria Nuland on Monday night, Nuland outlined the tough sanctions package being prepared by the administration in response to a potential Russian attack, but acknowledged that the US' options to deter an invasion are fairly limited, a person familiar with the briefing said.

It is still unclear whether Russian President Vladimir Putin has made the decision to invade, US officials stressed. But he has amassed enough forces, equipment and supplies near Ukraine's borders that he could move to attack on very short notice.