WASHINGTON (Reuters) - Secretary of State nominee Rex Tillerson expressed views on Wednesday at odds with President-elect Donald Trump’s positions on key foreign policy issues like nuclear proliferation, trade deals, climate change and relations with Mexico.

In a nine-hour Senate confirmation hearing, the former chief executive of oil company Exxon Mobil said he favored maintaining U.S. sanctions against Russia for now and that NATO allies were right to be alarmed by Moscow’s growing aggression.

Russia dominated much of the hearing because of concerns by Democrats and Republicans over Moscow’s interference in the U.S. presidential election and its 2014 annexation of Crimea from Ukraine and involvement in the Syrian civil war.

Questions soon moved to the threat posed by Islamic State, China’s behavior in the South China Sea, human rights and Tillerson’s ability to make a clean break from a career at Exxon Mobil to become America’s top diplomat.

Tillerson said his differences with Trump on some major issues would not necessarily put him at loggerheads with the White House.

He said everyone in Trump’s Cabinet would have the chance to discuss issues “and the president will decide.” He described himself as open and transparent.

In a stark departure from Trump, Tillerson said it would not be acceptable for some U.S. allies to acquire nuclear weapons. He also did not see the need for a Muslim registry, saying he did not support targeting any particular group.

Asked by Democratic Senator Edward Markey about Trump’s comments in interviews he would not oppose U.S. allies including Japan obtaining nuclear weapons, Tillerson replied: “I do not agree.”

Tillerson said he did not oppose the Trans Pacific Partnership trade deal, which Trump has criticized, but acknowledged the negotiated deal may not serve all U.S. interests.

Tillerson, however, left room for broad reversals or changes to Obama administration policies, in line with Trump’s positions, including trade with Cuba and the Iran nuclear deal, which he said ought to undergo a full review.

The hearing before the Senate Foreign Relations Committee was interrupted sporadically by protesters. Tillerson, 64, is expected to be confirmed by the Republican-controlled Senate.

‘OPEN, FRANK DIALOGUE’ WITH MOSCOW

Senators have expressed concern about Tillerson’s ties to Russia while at Exxon Mobil and Trump’s desire to improve relations with Moscow.

Tillerson refused to call Russian President Vladimir Putin a war criminal and kept the door open to a possible change in U.S. sanctions policy against Russia, saying he had not seen classified information on Russian meddling.

“I would leave things in the status quo so we are able to convey this can go either way,” Tillerson said, suggesting “open and frank” dialogue with Moscow to better understand its intentions.

He blamed Russia’s aggression toward Ukraine since 2014 on an “absence of American leadership” and said the United States should have taken stronger actions to deter Russia.

“I’m advocating for responses that will deter and prevent further expansion of a bad actor’s behavior,” he said.

Tillerson said it was a “fair assumption” Putin was aware of Russian efforts to interfere in the U.S. election. He said he had not discussed Russia policy with Trump, which Democratic Senator Robert Menendez said was “pretty amazing.”

In a tense exchange, Republican Senator Marco Rubio pushed Tillerson on whether he believed Putin was a war criminal, in reference to Russia’s military actions in support of Syria’s government.

“I would not use that term,” Tillerson said, adding: “Those are very, very serious charges to make and I would want to have much more information before reaching a conclusion.”

Rubio, who ran against Trump for the Republican presidential nomination, shot back: “There’s so much information out there. It should not be hard to say that Vladimir Putin’s military has conducted war crimes in Aleppo,” referring to the Syrian city recently retaken by government forces backed by Russia.

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He added: “I find it discouraging, your inability to cite that which I think is globally accepted.”

Tillerson sidestepped questions on human rights, declining to condemn countries like Saudi Arabia and the Philippines for rights abuses, saying he wanted to see the facts first.

Rubio told reporters later that he was unsure he could vote for Tillerson. As one of 11 Republicans on the 21-member panel, his support is key to Tillerson winning the committee’s backing.

IRAN DEAL REVIEW

Tillerson said he would recommend a “full review” of the nuclear deal with Iran reached with the United States and world powers. He did not call for an outright rejection of the 2015 accord in which Tehran agreed to curtail its nuclear program in exchange for relief from crippling economic sanctions.

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Trump has made contradictory statements about the deal and has threatened to dismantle it.

Tillerson said China should be denied access to islands it had built in the contested South China Sea. He added his approach to dealing with North Korea, which recently said it was close to carrying out its first test of an intercontinental ballistic missile, would be “a long-term plan” based on sanctions and their proper implementation.

Asked if he could make unbiased decisions after his time at Exxon Mobil, the world’s largest publicly traded oil producer, he said he would act in America’s interests.

Tillerson dodged a direct question on whether he believed climate change was caused by human activity.

“The risk of climate change does exist and the consequences of it could be serious enough that action should be taken,” he said, adding the ability to predict the effect of greenhouse gas was “very limited.”

Trump has called global warming a hoax perpetrated by China and has threatened to quit the Paris climate accord, a global agreement to curb emissions.

Tillerson called Mexico “a long-standing neighbor and friend of this country.”

Trump has said he will build a wall on the Mexican border, and in his 2015 presidential announcement speech described Mexican migrants to the United States as drug-runners and rapists.

LOBBYING

Tillerson’s responses were calm and measured, without any obvious reliance on notes.

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

On Wednesday, he said he never personally lobbied against sanctions and emphasized that he was not aware of Exxon Mobil directly doing so.

Tillerson later acknowledged he spoke to U.S. Treasury Secretary Jack Lew regarding gaps between American and European sanctions on Russia.

Democratic Senator Chris Murphy vigorously challenged Tillerson on the issue, saying he called a U.S. senator to express concerns over the measures, which “likely constitutes lobbying.” Exxon lobbied Congress regarding sanctions against Russia following the annexation of Crimea. The lobbying directly related to energy matters, according to regulatory filings.