WASHINGTON (Reuters) - Russia is engaging in aggressive and destabilizing actions that are threatening the rules-based international order, Samantha Power said on Tuesday in her last major speech as U.S. ambassador to the United Nations.

United States Ambassador to the United Nations Samantha Power addresses media at the United Nations in Manhattan, New York City, U.S., December 19, 2016. REUTERS/Andrew Kelly

In a blistering and detailed critique of Russia’s foreign and military policies, Power also called for maintaining U.S. sanctions on Moscow and supporting the NATO alliance, which U.S. President-elect Donald Trump has criticized.

Power, speaking to the Atlantic Council, a Washington, D.C. think tank, cited Russia’s intervention in Ukraine, support of the Syrian government in the country’s civil war and efforts to influence elections in the United States and other Western democracies. She concluded that “Russia’s actions are not standing up a new world order. They are tearing down the one that exists.”

Russia has repeatedly used a “deny and lie” strategy to evade responsibility for misdeeds on the international stage, Power said.

Trump has said he will seek to improve relations with Moscow, despite criticism that he is too eager to make an ally of Russian President Vladimir Putin and U.S intelligence reports that say Putin sought to influence the U.S. election in favor of Trump.

While Trump said in an interview with The Times of London this month that he would propose offering to end some sanctions on Russia in return for a nuclear arms reduction deal, Power urged against lifting U.S. sanctions too quickly.

“Easing punitive measures on the Russian government when they haven’t changed their behavior will only embolden Russia,” she said.

Power urged continued support for NATO after Trump, in the Times of London interview, had said the alliance was obsolete because it had not defended against terror attacks, even though it was still was very important to him.

Trump’s comments about NATO have raised concerns among members of his own party. While Trump has said the alliance has not battled terrorism, Republican U.S. Senator John McCain, in an interview with CNN on Tuesday, pointed out NATO allies’ response after the United States was attacked on Sept. 11, 2001.

“They were willing to send their young people to Afghanistan to fight, not because they were attacked, but because we were attacked,” he said. “And we should never forget that.”

Trump’s relations with Moscow are facing renewed scrutiny after an unsubstantiated report by a former British intelligence officer that Russia had collected compromising information about him.

The report was summarized in an addendum to a U.S. intelligence report presented to Trump and President Barack Obama this month.

Putin on Tuesday said he doubted Trump had met with prostitutes in a Moscow hotel room several years ago, as the material summarized in the addendum alleges. Reuters has not independently verified any of the claims in the dossier.