>> we do have a counter-provocation plan to deal with these situation, situation short of all-out war. >> reporter: when the u.s. saw the key units, u.s. commanders took the rare step over the weekend of ordering an immediate review of the war plan to defend the south. >> anytime the north koreans start playing games like this, you've got to take is seriously. you dough know what their next step will be. >> u.s. intelligence satellite imagery and electronic signals show disturbing north korean military movements, including activation of some air defense radars that might be able to detect incoming aircraft. deployment of additional artillery pieces near the dmz. the concern, north korean artillery could hit population centers such's sowell in the south. signs of a potential preparation for a scud missile launch and dozens of warships and