Russia has announced a new military withdrawal from Crimea. It says it has completed military exercises there and troops are returning to their permanent bases. Meanwhile, Kyiv has denied that its forces opened fire in the eastern Donbass region, after an earlier Russian state media report. Both sides are accusing each other of violating a ceasefire. The Kremlin says it will respond to Washington's security proposals on Thursday. Russia's initial demands include NATO's roll-back from eastern Europe and for Ukraine to not join the military alliance. The United States and NATO are skeptical over Moscow's claims of a draw-down of troops, and say an invasion is still possible.