Rex Tillerson signalled his intention to be "clear-eyed" about Moscow but refused to say whether he would back economic sanctions against Russia.
But while Rex Tillerson signalled his intention to be "clear-eyed" about Moscow, he refused to say whether he would back economic sanctions against Russia and acknowledged he has not discussed with Trump the incoming administration's position on Washington's former Cold War foe.
The former ExxonMobil chief executive's remarks at his confirmation hearing before the Senate Foreign Relations Committee came against a backdrop of controversy over alleged Russian interference in the US presidential election.
"While Russia seeks respect and relevance on the global stage, its recent activities have disregarded American interests," Tillerson said, without offering specifics.
"Russia today poses a danger, but it is not unpredictable in advancing its own interests."
Tillerson, whose entire professional career has been in the energy industry, has faced criticism for his business relations with Russian President Vladimir Putin and other authoritarian leaders.
But the 64-year-old stressed that as Washington's top diplomat, he will conduct a more robust US foreign policy than during Barack Obama's presidency.
To achieve 21st century stability, "American leadership must not only be renewed, it must be asserted," he said.
Trump says he would like closer US ties with Russia and Putin, but Tillerson appeared keen to assure lawmakers that he will hold a tough line on Moscow.
"Our NATO allies are right to be alarmed at a resurgent Russia," he said, expressing frustration that Washington did not take a more "forceful response" when Russia annexed Crimea.
"They require a proportional act, proportional show of force, to indicate to Russia that there will be no more taking of territory," Tillerson stated.
He also hit out at China, warning that the Asian power pursues its "own goals" and has not sufficiently helped rein in a nuclear-armed North Korea.
"China has proven a willingness to act with abandon in the pursuit of its own goals which at times has put it in conflict with American interests. We have to deal with what we see, not what we hope," Tillerson said.
"It has not been a reliable partner in using its full influence to curb North Korea," he added.
Beijing, North Korea's closest ally, is seen as critical to containing Pyongyang's nuclear weapons program.
Tillerson, however, said disagreements with Beijing on some issues should not preclude "productive partnership" on other matters.
And Trump, a billionaire businessman with property interests around the world, was impressed.
"The thing I like best about Rex Tillerson is that he has vast experience at dealing successfully with all types of foreign governments," Trump tweeted.
The Senate's Democratic minority will try to make life difficult for Trump's cabinet nominees.
Senator Ben Cardin warned Tillerson that operating an oil firm was far different than safeguarding American interests worldwide.
"Recent news accounts indicate Russia may well have information about Mr. Trump and they could use that to compromise our presidency," Cardin said, alluding to a leaked dossier of unsubstantiated reports that claim Russia gathered compromising personal and professional details about Trump.
"It cannot be business as usual," Cardin insisted.
Some Republicans have also raised concerns about Tillerson's candidacy.
If just three Republicans jump ship, Tillerson's nomination could be blocked, despite support from party heavyweights.
Republican Senator Marco Rubio asked Tillerson if he believed Putin is a "war criminal" for the Russian military's attacks on Aleppo, Syria.
"I would not use that term," a steely Tillerson said.
While his Russia ties have faced scrutiny, number two Senate Republican John Cornyn said Tillerson "understands how to separate friendships and business. He knows who he works for."
Until he stepped down from ExxonMobil on New Year's Eve, Tillerson was also director of Exxon Neftegas, an affiliate that operates the Sakhalin-1 field in Russia's Far East.
The US parent firm was chasing greater investments in Russia, including Arctic fields, and Tillerson was a familiar and popular figure in Moscow, awarded an Order of Friendship medal by Putin in 2012.
Tillerson was a staunch opponent of US and international sanctions against Russia for its aggressive behavior in Ukraine, where it annexed the Crimea region.
On Wednesday, under questioning from Democratic Senator Robert Menendez, Tillerson would not say whether he would support fresh sanctions on Moscow, suggesting that "by design" they could harm American business.
Washington and Moscow could either be adversaries or partners, he said, but likely would never rise to a warm friendship because of their difference in values.
"We're not likely to ever be friends," Tillerson said.