After months of inching through minefields, villages and open steppes in grueling combat, Ukrainian forces are making somewhat bigger advances along two major lines of attack, according to analysts, Ukrainian officials and Russian military bloggers. Although Ukraine has not advanced more than 10 to 12 miles on either vector of attack, its gains are important in that it is compelling Moscow to divert forces from other parts of the front line, military analysts say. The Institute for the Study of War, a Washington-based think tank, called the advances “tactically significant,” saying Moscow’s redeployment would most “likely further weaken Russian defensive...