watching what could be another ominous sign in the crisis between russia and ukraine. two senior defense officials tell cnn there are indications russia has positioned blood supplies near ukraine's border. >> you add that to a buildup of troops and military equipment and u.s. officials say it could be another sign that russia is planning an invasion where casualties would have to be treated. meantime, ukraine's deputy defense minister is pushing back forcefully on that report, they're denying that it's true. >> cnn international diplomatic editor nic robertson is with us from moscow. talk to us about what you're learning regarding russia potentially positioning these blood supplies along the border. >> reporter: russia continues to say that this is all military training and certainly many military experts would say blood supplies would be part of military training exercises, you know, they were put the medical