April 25, 2017 0835 GMT
During a Senate confirmation hearing on Wednesday, the former chairman and CEO of ExxonMobil, the world's largest publicly traded oil producer, was grilled over the matter as well as his stance on the climate change.
"I would not use that term," Tillerson said in response to Republican Senator Marco Rubio, who asked if he believed the Russian president should be called a “war criminal” over the country’s support for Syria. "Those are very, very serious charges to make and I would want to have much more information.”
On the other hand, the 64-year-old asserted that he supported maintaining current US sanctions against Moscow, adding that NATO allies have the right to be concerned about what the West refers to as “Russian aggression.”
"I would leave things in the status quo so we are able to convey this can go either way," he said. "I would recommend maintaining the status quo until we are able to engage with Russia and understand better what their intentions are."
The former corporate titan was also grilled over his comments on climate change, a scientific fact that the GOP dos not even acknowledge, calling it a “risk.”
"The risk of climate change does exist and the consequences of it could be serious enough that action should be taken," he said, refusing to say if it was caused by human activity. "The increase in greenhouse gas concentrations in the atmosphere are having an effect. Our abilities to predict that effect are very limited."
He also commented on a nuclear deal negotiated by the administration of US President Barack Obama with Iran along with four other world powers in 2015.
Tillerson asserted that he would call for "full review" of the Joint Comprehensive Plan of Action (JCPOA).
Trump has previously threatened to reject the deal on his first day in office; he has also said that he would renegotiate it.
The hearing came at a time that ties between Russia and the US were in tatters over the US intelligence community’s conclusion that Moscow meddled in the 2016 vote that put Trump at helm.
Citing multiple unnamed officials with direct knowledge of the matter, CNN reported Tuesday that Russia is in possession of "compromising" personal and financial information about the New York billionaire and former reality TV star.
The allegations, denied by Moscow, were also dismissed by the president-elect, citing "fake news."