NATO chief Jens Stoltenberg has called on Russia to withdraw its forces and military equipment from Ukraine and to stop supporting separatists in eastern Ukraine.
Stoltenberg made his comments on June 15 after a meeting of NATO defense ministers in Brussels that was also attended by Ukrainian Defense Minister Stepan Poltorak.
Russian officials have repeatedly denied sending troops or military hardware to Ukraine, despite evidence to the contrary.
Stoltenberg said the alliance will continue to stand by the Ukrainian government and will never recognize Russia's 2014 "illegal and illegitimate annexation of [the Ukrainian peninsula of] Crimea."
He added that in response to Russian military actions in Ukraine, NATO has "stepped up its support for Ukraine."
Stoltenberg said that Russia continues to support separatists in southeastern Ukraine by supplying them with equipment and advisers.
He said that adherence to the Minsk accords is the only way to end the fighting in eastern Ukraine, which has killed more than 9,300 people since 2014.
Leaders from NATO's 28 member countries will meet for a July 8-9 summit in Warsaw where they are expected to approve plans to station military battalions in the three Baltic states and Poland.