The Kremlin on Friday rejected allegations it was behind a plane crash that is presumed to have killed mercenary leader Yevgeny Prigozhin, who conducted a brief but shocking mutiny in Russia two months ago.

Prigozhin, whose brutal fighters were feared in Ukraine, Africa and Syria, was eulogized Thursday by President Vladimir Putin, even as suspicions grew that the Russian leader was behind the crash that many saw as an assassination.

A preliminary U.S. intelligence assessment concluded the plane was downed by an intentional explosion. One of the U.S. and Western officials who described the assessment said it determined that Prigozhin was “very likely” targeted and that the explosion falls in line with Putin’s “long history of trying to silence his critics.”

The officials, who spoke on the condition of anonymity because they were not authorized to comment, did not offer any details on what caused the explosion, which was widely believed to be vengeance for the mutiny in June that posed the biggest challenge to Putin’s 23-year rule.

But Kremlin spokesperson Dmitry Peskov flatly rejected the allegations.

“Right now, of course, there are lots of speculations around this plane crash and the tragic deaths of the passengers of the plane, including Yevgeny Prigozhin,” Peskov told reporters during a conference call. “Of course, in the West those speculations are put out under a certain angle, and all of it is a complete lie.”

Prigozhin was listed among those aboard the plane.

Asked by The Associated Press whether the Kremlin has received an official confirmation of Prigozhin’s death, Peskov referenced Putin’s remarks from a day earlier: “He said that right now all the necessary forensic analyses, including genetic testing, will be carried out. Once some kind of official conclusions are ready to be released, they will be released.”

Britain’s Defense Ministry said the presumed death of Prigozhin could destabilize his Wagner Group of private military contractors.

His “exceptional audacity” and “extreme brutality” permeated the organization “and are unlikely to be matched by any successor,” the ministry said in a statement.