and brushing asides warnings from the west. the crisis in ukraine it is causing. jennifer griffin has more from the pentagon. the pentagon is watching closely reports that armed troops sympathetic to russia just stormed the gates of the main air defense command centerrer in sevastopol. the pentagon estimates there are 20,000 russian troops in crima, i m told there will be no change to u.s. military posture, however. the f-15 fighter jets sent to the baltics were to reassure nato allies. the pentagon does not want to escalate or give putin a pretext to invade elsewhere. the pentagon s big concern is not the number of russian troops, it s their actions. it s less important the number than it is what they re doing. u.s. defense officials tell me that as of this morning, russia was poised for a large