Speaking to NATO foreign ministers on Tuesday, Pompeo said the U.S. was willing to start the process of leaving the treaty, citing alleged Russian violations.
While Stoltenberg said there would now be an intense diplomatic push to try to convince Russian Federation to give up what Pompeo said were "multiple battalions of the SSC-8 missiles", Washington is set to start to pull out in February, prompting a six-month withdrawal period under the accord, diplomats said.
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US Secretary of State Mike Pompeo told NATO ministers that Washington would begin the process of withdrawing from the 1987 Intermediate-Range Nuclear Forces Treaty (INF) within 60 days if Moscow did not start complying with the terms of the pact.
Russia's President Vladimir Putin (L) is pictured during a meeting with India's Prime Minister Narendra Modi (R) and China's President Xi Jinping (out of frame), in the sidelines of the G20 Summit in Buenos Aires.
"I am certain that, at some time in the future, President Xi and I, together with President Putin of Russian Federation, will start talking about a meaningful halt to what has become a major and uncontrollable Arms Race", Trump said on Twitter.
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The treaty banned all land-based cruise missiles with a range of between 310 miles and 3,417 miles.
Russia-U.S. ties have sunk to post-Cold War lows over the Ukrainian crisis, the war in Syria, the allegations of Russian meddling in the 2016 U.S. presidential election and other irritants. The arms race is just a fraction of that amount.
In Moscow, Foreign Ministry spokeswoman Maria Zakharova said that "Russia strictly complies with the provisions of the treaty, and the American side is aware of that".
But it is unclear what more North Atlantic Treaty Organisation would do beyond the sea patrols and air policing it already does in the region. Three NATO allies on the Black Sea - Bulgaria, Romania and Turkey - are also taking individual measures.
"We need to create a coordinated response to the actions of Russia", Klimkin said, adding that he raised "a set of practical steps with a number of proposals" at the meeting as to how NATO, Ukraine and Georgia might do that together.
Or warning them: "I think Trump is signaling/warning both if they don't come to the table they will face a US arms buildup that they will have to match", James Jay Carafano of the conservative Heritage Foundation told the Military Times.
Some European allies suspect that Trump could give notice in coming months that the U.S.is leaving the treaty.