Russians seek to advance near places most never heard of

 ISW:

Russian forces intensified efforts to encircle and capture Severodonetsk on May 21 and will likely continue to do so in the coming days as efforts on other axes of advance, including Izyum, remain largely stalled. Russian troops in Luhansk Oblast will likely move to capitalize on recent gains made in the Rubizhne-Severodonetsk-Luhansk-Popasna arc to encircle and besiege Severodonetsk—the final Ukrainian strongpoint in Luhansk Oblast. Russian milbloggers are hypothesizing on the success of Russian tactics in the area and have dubbed it the Battle of Severodonetsk—emphasizing that this is the preliminary line of effort in the Donbas theatre.

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The Russians appear to be concentrating their forces on communities that are not major cities in Ukraine. 

See, also:

Russia tries to rebound as prospects for victory fade