Russia's actions during the U.S. presidential election and its behavior toward Ukraine dominated the confirmation hearing of Rex Tillerson, President-elect Donald Trump's pick for secretary of state, as senators pressed him on Wednesday on how he would deal with aggression from Moscow.

Tillerson, 64, the former chief executive of Exxon Mobil Corp, faced a grilling on his views of Russian President Vladimir Putin and tough questioning from Republican Senator Marco Rubio about whether he believed Putin was a war criminal. Rubio specifically referred to Russia's military actions in support of the Syrian government in the Syrian civil war.

"I would not use that term," Tillerson said.

Tillerson also declined to say whether he would support upholding President Barack Obama's executive order imposing fresh sanctions, which was in retaliation for what Washington charges was Moscow's hacking and other efforts to tilt the 2016 presidential election in Trump's favor.

Tillerson said it was "a fair assumption" that Putin was aware of Russian efforts to interfere in the U.S. election.

The central question senators will pose to Tillerson is how he can pivot from a Big Oil "dealmaker" protecting the interests of shareholders to being America's top diplomat, and whether he shares Trump's view that relations with Moscow should be improved.

The hearing was interrupted by sporadic protests.

In prepared opening remarks, Tillerson said Moscow should be held accountable for its actions and NATO allies are right to be alarmed by Moscow's behavior. Tillerson did not mention Russia's alleged hacking of the election in his opening remarks and said he did not discuss Russia policy during a meeting he had recently with Trump.

Bob Corker, chairman of the U.S. Senate Foreign Relations Committee, has said he expects the Republican-controlled Senate will easily confirm Tillerson.

On Wednesday, Corker said Tillerson's background as a business executive made him an "inspired choice" for the job. Corker emphasized that Tillerson had not met Trump until recently and would not be able to speak for the president-elect during the hearing.

Tillerson's confirmation hearing comes at a time of rising tensions with Russia.

U.S. intelligence agencies have concluded that Russia was behind the hacks of political figures in an effort to help the Republican Trump defeat Democratic candidate Hillary Clinton in the Nov. 8 election. Moscow has denied the allegations.

In another revelation, also denied by Moscow, two U.S. officials said on Tuesday evening that classified documents that the heads of four U.S. intelligence agencies presented last week to Trump included claims that Russian intelligence operatives have compromising information about him. Trump dismissed the reports, first made by CNN, as "fake news."

Tillerson opposed U.S. sanctions against Russia in 2014 over its annexation of Crimea from Ukraine because he said he thought they would be ineffective.

SANCTIONS ON RUSSIA

During the hearing, Tillerson said sanctions were by design meant to disrupt American business overseas. Democratic Senator Robert Mendendez disputed that interpretation, saying sanctions were about putting patriotism over profit.

"I have never lobbied against sanctions personally," Tillerson responded.

He said he would support maintaining U.S. sanctions on Russia until the United States further develops its approach to the country.

"I would leave things in the status quo so we are able to convey this can go either way," Tillerson said in response to a question on whether he thought right now is the right time to lift sanctions on Russia.

On Tuesday, 10 senators - five of whom sit on the Senate Foreign Relations Committee that will vet him - introduced legislation to impose even tougher sanctions on Moscow, and promised to grill Tillerson about whether he would back them.

Setting a tough tone for the hearing, the panel's top Democrat, Senator Ben Cardin, regretted that remarks Tillerson submitted ahead of the hearing did not mention the "direct, confirmed cyberattack by Russia on America," although he did criticize U.S. leadership.

"It is frankly not too great a distance from Exxon's business partnerships to Putin's Kremlin-controlled slush funds essential for his 'disinformation' campaigns around the world," Cardin, a co-sponsor of the sanctions bill, said in prepared remarks.

In 2012, Tillerson received the "Order of Friendship" award from Putin. The same year, Exxon deepened its cooperation with Russian oil company Rosneft to expand an oil drilling project in the Arctic after U.S. sanctions over Ukraine were imposed.

At the time of the sanctions, Russian oil magnate Igor Sechin told Reuters he would miss three things: exploring U.S. culture, the chance to show his children American landscapes and riding motorbikes with Tillerson.