Kyiv on heightened alert as Russian forces close in on all sides

https://edition.cnn.com/2022/02/26/europe/ukraine-russia-invasion-saturday-intl-hnk/index.html

See also 

https://edition.cnn.com/europe/live-news/ukraine-russia-news-02-27-22/index.html

White House responds to Russia's decision to put deterrence forces on high alert

https://edition.cnn.com/2022/02/27/politics/russia-nuclear-high-alert-white-house-reaction/index.html