WASHINGTON -- Outgoing White House national security adviser H.R. McMaster has called for stronger measures against Russian "threats" and "provocations," arguing that Russian President Vladimir Putin is mistaken in thinking the West will not push back against the Kremlin's "hybrid warfare."

The comments were some of the strongest to date on Russia by McMaster, whose last day at the White House will be next week.

"For too long, some nations have looked the other way in the face of these threats. Russia brazenly, and implausibly, denies its actions, and we have failed to impose sufficient costs,” McMaster said in an April 3 speech at the Atlantic Council in Washington.

McMaster cited what he called Russia's use of "hybrid warfare" -- using economics, politics, and cybertools to undermine adversaries -- and insisted that Moscow would not prevail over the West.

He also cited the poisoning of ex-Russian double agent Sergei Skripal, who remains hospitalized after being exposed in Salisbury, England, to a military-grade nerve agent in March -- an attack the British government has accused Russia of carrying out.

“Mr. Putin may believe that he is winning in this new form of warfare. He may believe that his aggressive actions in Salisbury, in cyberspace, in the air, and on the high seas can undermine our confidence, our institutions, and our values,” McMaster said. “Perhaps he believes that our free nations are weak and will not respond to his provocations. He is wrong."

McMaster's hawkish approach to Russia contrasted with President Donald Trump's often conciliatory rhetoric toward Moscow. His successor, former UN Ambassador John Bolton, shares similarly tough views on Russia.