Russian troops and heavy weaponry, including tanks, artillery and anti-aircraft systems, have streamed across the border into Ukraine in recent days, U.S. Defense Department and military officials confirmed Wednesday to NBC News.
The exact number of Russian troops and vehicles now operating within eastern Ukraine remains unclear. However, U.S. military officials say the Russians now have a "permanently garrisoned force" on the Russian side of the border, including seven combat brigades and some seven thousand ground troops. U.S. officials also confirm that the Russians have begun "militarizing" Crimea, the Ukrainian peninsula seized by Russian forces in March.
While officials did not describe the military convoys as an "invasion force," they admitted that the latest incursion had effectively eliminated the border between the two nations, granting Moscow free reign to reinforce pro-Russian separatists battling Ukrainian forces in defiance of the cease-fire agreement signed at Minsk, Belarus, in September.
"It appears they may be digging in to support the separatists, not mount a challenge" one senior U.S. official told NBC News.
Moscow, which has consistently deployed a combination of indignant denials and secretive military action to advance its interests in Eastern Europe, dismissed the allegations entirely. “We've already stopped taking note of the unfounded statements by NATO’s Supreme Allied Commander in Europe, Gen. Philip Breedlove, on Russian military columns he supposedly saw intrude the Ukrainian territory,” Russian Defense Ministry Spokesman Maj. Gen. Igor Konashenkov told the state-run news agency Itar-Tass on Wednesday.
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With the September cease-fire agreement quickly falling apart, the Ukrainian government announced it was redeploying troops to the contested Donbas region, to prevent a possible military offensive by the newly-reinforced pro-Russian separatists.
"Russia's actions in Ukraine are not only a threat to the countries in Russia's immediate vicinity, but also to the international order," U.S. Ambassador Samantha Power said Wednesday at an emergency meeting of the United Nations Security Council, detailing a list of transgressions by Moscow. Russia, a member of the five-nation U.N. Security Council, has so far used its veto power to prevent any meaningful action on the Ukraine issue.
Meanwhile, U.S. Secretary of State John Kerry spoke with Russian Foreign Minister Sergei Lavrov on Wednesday to express his "ongoing concerns about escalating tensions," and "the need to abide by the Minsk Protocols."
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In a press briefing Wednesday, State Department spokesperson Jen Psaki did not independently confirm that Russian military forces had crossed the border with Ukraine, but stood by reports on troop movements issued by NATO and the Organization for Security and Co-operation in Europe (OSCE), the group responsible for overseeing the terms of the cease-fire and monitoring the Ukraine-Russia border.