ravage for cities, officials say putin's playbook will likely include the systematic kidnapping of local leaders. >> this is a terror tactic, grab local officials, depose local governments, put proxies in their place. >> at least four mayors have already been captured. one has been released, they say, as part of a prisoner swap. the mayor of melitopol. his subsequent release and use of an expletive during a celebratory phone call made president zelenskyy crack a smile. >> but fear is spreading. today, this refugee told us the mayor of her city in southern ukraine was in hiding. in another town, about 75 miles from kyiv, the mayors now surrounded by armed guards. >> the russian army there changing tactics. that was nbc's gabe gutierrez