correspondent andrea mitch am has the details for us. reporter: with fears rising that russia could invade ukraine, president biden considering a major show of force near russia putting up to 8500 u.s. troops on heightened alert mostly as part of a nato response force. military action from russia could come at any time. the president from camp david over the weekend reviewing pentagon proposals to move thousands of troops from nato countries over to ukraine and fly bombers over the region and ships to the sea and putting more troops on stand by and sending additional fighter jets and war ships. what this is about is reassurance to our nato allies. from the situation room, president biden insisting they are united. i had a very, very good meeting with european lete leaders. but nato is divided. stalling on german-made