The apparent death of Yevgeny Prigozhin, the leader of Russia's private mercenary firm Wagner Group, likely gives Russian President Vladimir Putin a tighter grip on his country, a former U.S. national security advisor told CNBC.
Prigozhin was on the passenger list of a plane involved in a fatal crash on Wednesday in the Tver region of Russia, outside Moscow.
"My own sense is this [incident] probably strengthens Putin's hand considerably inside Russia," John Bolton, who served as national security advisor under the Trump administration, told CNBC's Dan Murphy on Thursday.
"I'd never bought the argument that the mutiny two months ago was a real direct threat to Putin — I think his position was weakened, but now I think it's stronger," Bolton said, referencing the short-lived rebellion by Prigozhin and his Wagner contingent against the Russian government, which took place over June 23-24.
Before the insurrection attempt, the 62-year-old paramilitary leader, once a close confidant of Putin, had spent months vocally criticizing his country's top brass for what he said was their corruption and failure to adequately support and prepare Russian troops fighting in Ukraine. His forces, known for their particularly violent battlefield tactics, spearheaded a number of battles for Russia on the Ukrainian front.
An apparent deal was made between Prigozhin and Putin after the aborted coup. Under the terms of the agreement, the Wagner Group leader and his forces would relocate to Belarus, with Prigozhin pledging to leave Russia for good.
Several analysts looking at the situation in Russia at the time of the coup attempt saw the event as an embarrassing blow to Putin's authority. Many also predicted that Prigozhin's days were likely numbered.
"I think a lot of the criticism that Prigozhin was making … was not that they were against the invasion of Ukraine, [but] they were against the failure to win in Ukraine," Bolton told CNBC.
"Putin's hand I think, is strengthened now. And I think we're at a very critical period in the battlefield in Ukraine because of the stalled spring offensive by the Ukrainians."
The former national security official and American ambassador to the U.N. also expressed concern over the slow progress of the long-anticipated Ukrainian counteroffensive, which Kyiv and its allies had hoped would decisively turn the tide against Moscow.
"I'm very worried, frankly, from that point of view, that now, especially, the Kremlin will take the advantage of September, maybe early October, to try and move diplomatically to achieve what they've not achieved on the battlefield," Bolton said. "So I think we're in for a perilous time ahead here."
Putin expressed his condolences following Prigozhin's demise in a televised address Thursday.
"With regard to this plane crash, first of all, I want to express my sincere condolences to the families of all the victims. It's always a tragedy," Putin said.
"I've known Prigozhin for a long time, since the early '90s. ... He was a talented man, a talented businessman. He worked not only in our country — and with result — but also abroad," he added, referencing Prigozhin's contracts in Africa.
The Russian president added that an investigation into the explosion that brought down the private jet was already underway.
— CNBC's Karen Gilchrist contributed to this report.