Donald Trump's nominee for secretary of state Rex Tillerson has been grilled by senators over his views on Russia at his confirmation hearing.
The former chairman of Exxon Mobil, an unconventional pick for secretary of state, has faced scrutiny over his relationship with Russian president Vladimir Putin, views on Russia as well as his attitude towards climate change.
Tillerson appeared to adopt a tough line on Russia telling his confirmation hearing: "Russia today poses a danger, but it is not unpredictable in advancing its own interest ... Our Nato allies are right to be alarmed at a resurgent Russia."
But he added that it was "in the absence of American leadership that this door was left open".
Later, responding to a question by Democratic senator Ben Cardin, Tillerson said he would support maintaining US sanctions on Russia until America further developed its approach to the country.
He also told the Senate Foreign Relations Committee it was a "fair assumption" that Russia's Vladimir Putin was aware of Russian efforts to interfere with the 2016 US election.
At one point during the hearing a small protest broke out in the chamber and a woman carrying a banner shouted "Rex Tillerson, I reject you," as police escorted her from the room.
Mr Tillerson would not be drawn by senators Marco Rubio and Robert Menendez who pressed him over whether Russia and Mr Putin should be considered guilty of war crimes.
He also said the US needed to move away from always considering Russia to be an adversary, and that it could be a partner at times.
While many of the questions directed at him were on Russia, Mr Tillerson himself spoke more of China and combating Islamist terrorism in his opening statement.
On climate change, Mr Tillerson somewhat equivocal, saying: "The risk of climate change does exist and the consequences of it could be serious enough that action should be taken."