(Bloomberg) — Former South Carolina Governor Nikki Haley assailed Donald Trump’s foreign policy, condemning the former president for his silence on the death of Russian opposition leader Alexey Navalny.

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“Either he sides with Putin and thinks it’s cool that Putin killed one of his political opponents, or he just doesn’t think it’s that big of a deal,” Haley said Sunday on ABC’s This Week. “I think it’s important to stand with the Russian people who believe Navalny was really talking for them.”

Haley, who was Trump’s ambassador to the United Nations, has targeted her former boss on foreign policy in recent days as she fights to stave off a defeat in her home state in the Feb. 24 Republican primary. Polls show Haley, Trump’s only remaining opponent for the GOP presidential nomination, trailing by double digits.

Haley blamed Navalny’s death on Russian President Vladimir Putin, joining accusations by other Western leaders including President Joe Biden. Russia’s prison service said Navalny fell sick at a maximum-security camp where he was imprisoned and medical staff were unable to revive him.

“You look at this hero, he was fighting corruption,” she said. “He was fighting what Putin does and what did Putin do? He killed him just like he does all his political opponents.”

Read more: Putin Seeks Revenge on a World Order He Once Wanted to Join

Navalny, 47, was a leading voice against Putin, drawing his ire by investigations that exposed corruption at state companies and videos on the lavish lives of senior officials.

Haley has made her foreign policy chops a centerpiece of her presidential bid, vowing to get tough with China and other US adversaries abroad. She has criticized Trump’s threats to NATO member countries that fall short of defense-spending commitments and his obstruction of further US aid to Ukraine.

Haley doubled-down on her criticism of Trump at a town hall on Sunday evening, while adding that she would be tough on NATO allies behind the scenes rather than in public if they weren’t meeting their commitments.

“I will absolutely put the hammer on our NATO countries that they do have to carry their weight, but you do that behind closed doors,” Haley said at the forum hosted by Fox News. “You do that and let them know that the United States is not gonna carry the burden, but you don’t do it in the eyes of our enemies.”

Her views make her an outlier in her party, where the base has largely embraced Trump’s more isolationist views. But it could bolster her among Democrats and independent voters.

(Updates to include Haley comments in the 8th and 9th paragraphs. An earlier version of this story corrected Navalny’s first name.)

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