“Putin did this. The same Putin who Donald Trump praises and defends,” Nikki Haley said. Mr. Trump has so far kept silent since reports that Aleksei A. Navalny died.

Washington: Many Republicans lined up to condemn President Vladimir V. Putin of Russia on Friday after Russian authorities reported the death of Aleksei A. Navalny, the outspoken opposition leader.

But Nikki Haley went further, using criticism of Mr. Putin to attack former President Donald J. Trump, her rival in the G.O.P. primary, for his past remarks that praised Mr. Putin.

“Putin did this. The same Putin who Donald Trump praises and defends,” Ms. Haley, a former governor of South Carolina who served Mr. Trump’s ambassador to the United Nations, wrote on the social media platform X on Friday.

She referenced comments that Mr. Trump made in 2015, during his first run for president, when he told ABC’s George Stephanopoulos that, “In all fairness to Putin, you’re saying he killed people. I haven’t seen that.”

Russian authorities announced on Friday that Mr. Navalny, an anticorruption activist who was openly critical of Mr. Putin and was serving multiple sentences that would likely have kept him in prison until 2031, had died in a prison inside the Arctic Circle. President Biden said on Friday afternoon that U.S. officials did not have a full understanding of the situation’s circumstances, but that he believed “there is no doubt that the death of Navalny was a consequence of something that Putin and his thugs did.”

Mr. Trump has not yet commented publicly on Mr. Navalny’s death, prompting Ms. Haley to also seize on his silence. In another post to X, she wrote that, “Putin murdered his political opponent and Trump hasn’t said a word after he said he would encourage Putin to invade our allies. He has, however, posted 20+ times on social media about his legal drama and fake polls.”

Since reports of Mr. Navalny’s death surfaced Friday morning, Mr. Trump delivered posts on Truth Social that criticized Fani T. Willis, the prosecutor in his Georgia election interference case; said that the world had “experienced misery, destruction, and death” during Mr. Biden’s term in office; and promoted his appearance at “Sneakercon” in Philadelphia on Saturday. But as of Friday afternoon, there was no mention of Mr. Putin or Mr. Navalny.

Ms. Haley has been increasingly critical of Mr. Trump’s approach to foreign policy, and specifically his attitude toward Mr. Putin. She told voters at recent stops in South Carolina that Mr. Trump had taken “the side of a thug,” after the former president said in South Carolina last weekend that he might “encourage” Russia to attack N.A.T.O. allies delinquent on payments to the military alliance.

Her campaign issued a statement later on Friday that attempted to further connect Mr. Trump’s past praise to his recent comments.