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(CNN) A day after Russia's prime minister spoke of a renewed "Cold War" between his country and the West, a senior U.S. senator accused Moscow of treating Syria "as a live-fire exercise" for its military as it sought to carve out a sphere of influence in the Middle East.

Speaking Sunday at the Munich Security Conference in Germany, U.S. Sen. John McCain criticized Russian President Vladimir Putin's intervention in Syria's nearly five-year civil war.

"Mr. Putin is not interested in being our partner," said McCain, chairman of the U.S. Senate's Armed Services Committee, adding that the Russian president wanted to "shore up the Assad regime."

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Since intervening in the Syrian conflict in September, Russia has pursued a devastating air campaign from Hmeymim air base in Syria's Latakia province , which has helped swing momentum in favor of Syrian President Bashar al-Assad.

McCain continued: "He wants to re-establish Russia as a major power in the Middle East. He wants to use Syria as a live-fire exercise for Russia's modernizing military, he wants to turn Latakia province into a military outpost from which to harden and enforce a Russian sphere of influence -- a new Kaliningrad, or Crimea -- and he wants to exacerbate the refugee crisis and use it as a weapon to divide the trans-Atlantic alliance and undermine the European project."