The rapid-fire territorial takeover is slicing right into a huge swath of ground that Putin claimed as Russia's own on Friday. The unilateral annexation, following staged referendums in occupied territory, has gone unrecognized by virtually the entire world. It has been derided as an illegal land grab by the United Nations, Ukraine, the U.S. and many other countries. 
    With it, Putin declared the four Ukrainian regions of Donetsk, Luhansk, Zaporizhzhia and Kherson, all Russian soil.
    As Ukraine's forces push their gains in those regions, reclaiming territory, the mayor of one occupied city told CBS News he expects to see a massive escalation in the seven-month war.
   Ivan Federov, the exiled mayor of Russian-occupied Melitopol, in the Zaporizhzhia region, was kidnapped in the early days of the war but released in a prisoner swap. He said Putin's decision to declare the annexation of the four regions was a "new level of aggression," and he believes the Russian strongman leader may well "use nuclear weapons now on these territories."
    "I expect it," Federov said. "He is crazy."  
    Fears of a tactical Russian nuclear strike — using small-scale atomic weapons to target a specific area — have put cities like Dnipro on edge. Russian forces have already stepped-up attacks on civilian targets in such places, west of the ground they hold.
    CBS News saw the vast crater left when a Russian missile slammed down recently in Dnipro, completely destroying a home in a residential neighbohood. It wasn't clear what the Russians could have been targeting. Neighbors told CBS News that a grandmother, a mother and two small children were killed as they slept.  
    Tearful residents paid tributes, laying flowers and toys to remember the young lives taken in a seemingly random rocket attack, miles from the front line. 
    Other Dnipro residents wandered around in shock and disbelief after the strike — and in fear, of where and when the next rockets might strike, and what they could be carrying.