First on CNN: Intelligence from field has White House 'very concerned' about Russia invading more of Ukraine – possibly soon

(CNN) - Based on intelligence, Obama administration officials are very concerned the Russians are not being truthful when they say their forces near Ukraine's eastern and southern borders are merely there for training exercises, sources tell CNN.

Officials assess that Russia – as early as coming days – could use any number of pretexts to justify further military incursions into Ukraine.