our top military commander, general walters, has activated nato s chemical, biological, radiological and nuclear defense elements and allies are deproi v ploying additional chemical and biological and nuclear defenses to reinforce our existing groups. nbc news has confirmed what was first reported by the new york times, that the white house has assembled a team of national security officials to start mapping out how to respond if vladimir putin does deploy chemical, biological, or, yes, even nuclear weapons. a pentagon official says russian forces have stalled, and ukrainians have pushed back others. the official says another assault on the city of chernihiv has stalled an troops have been unable to advance. nato is reporting between 7,000 and 15,000 russian soldiers, as