KAZAN Kiev on Dec. 21 staged a major drone attack on the Russian city of Kazan , 1,000 kilometers from the frontier, the latest in a series of escalating aerial attacks in the nearly three-year conflict. A drone smashed into a high-rise apartment building in the city of more than 1.3 million, damaging a skyscraper but leaving no victims, local officials said. Though attacks so far into Russian territory are rare, Kazan and the surrounding oil-rich region of Tatarstan have previously been