On Aug. 15, as a Russian "aid convoy" of 280 trucks neared the Ukrainian border, NATO said that a separate "incursion" of Russian military forces had crossed into Ukraine. The Russian forces are reportedly in eastern Ukrainian territory held by Russia-backed separatist rebels, according to NATO and Ukrainian government officials. Some reports suggest that there may be open fighting between Ukrainian military forces and the Russian incursion, but it's far from clear whether that's true or what precisely is happening on the ground.
Russia's War Against Ukraine
Vox: Did Russia and Ukraine just start a war? What we know and don’t know
Ukrainian servicemen sit on an armoured vehicle with a Ukrainian flag as a convoy of Ukrainian forces drive towards the eastern city of Debaltseve.