Russian tanks, artillery, and soldiers have crossed into Ukraine in recent days, according to Kiev, which described it as a stealth invasion. The attacks "essentially have opened a new, third front in the war" between pro-Russia rebels and Ukraine, the New York Times reports. Some of the retreating Ukrainian soliders expressed an unwillingness to fight and felt they were "cannon fodder." According to a Ukrainian military spokesman, Ukraine still controls the city of Novoazvosk, but 13 men died defending it. “Russia is clearly trying to put its finger on the scale to tip things back in favor of its proxies,” said a senior U.S. official. On Monday, Ukraine captured Russian paratroopers that had been secretly deployed over the border.