It is an issue that was raised with Russia when there was a NATO-Russia council. Since the invasion and acquisition of Crimea, the first time since World War II that a European power has grabbed a piece of territory of another country, the NATO-Russia council doesn't exist anymore. That was a subject that factored into NATO's discussions with the Russians, and of course it was always an issue with the U.S. and Russia as well, that whole tactical nuclear weapons—
On February 15th, 2018. See this statement in context.