KUZHENKINO, Aug 25 (AFP) - Russian President Vladimir Putin broke his silence on Thursday (Aug 24) on the plane crash a day earlier that reportedly killed mercenary boss Yevgeny Prigozhin and other senior members of the Wagner paramilitary group.

In televised comments Putin offered his "sincere condolences to the families of all the victims", describing the crash as a "tragedy".

As well as Prigozhin, the other nine people on board also died.

Wednesday evening's crash took place exactly two months after Prigozhin led a rebellion against Moscow's top military brass, considered by some observers to have been the biggest threat to Putin's long rule.

Although Moscow opened a probe into violations of air traffic rules, investigators have been silent since, as speculation of a possible assassination has grown.

Ukraine's President Volodymyr Zelenskyy insisted Kyiv had nothing to do with the incident. "I think everyone knows who this concerns," he said, in what appeared to be a reference to Putin.

"There is a court in The Hague, there is a court of God. But Russia has an alternative (court) - President Putin," he said when asked again about the air crash later Thursday.

When Putin broke his silence on Thursday he paid a qualified tribute to the mercenary boss and the paramilitary group he led.

"I knew Prigozhin for a very long time, since the early 90s. He was a man of complicated fate, and he made serious mistakes in his life, but he achieved the right results," Putin said.

In an address to Russians during the Wagner rebellion on Jun 23 to Jun 24 in which he warned against "civil war", Putin had called Prigozhin - once his ally - a "traitor".

But on Thursday, he said the Wagner members who had died in the crash had made a "significant contribution" to Moscow's offensive in Ukraine.

They had shared a common cause, Putin said, adding: "We remember that, we know that, and we will not forget that."

He said the investigation into the crash would take time, but added: "It will be conducted in full and brought to a conclusion."

Some Western leaders expressed doubts that the crash had been an accident.

"There's not much that happens in Russia that Putin's not behind," said US President Joe Biden, after having said he did not know what happened.

France saw "reasonable doubts" about the crash, while Germany said it followed a pattern of "unclarified" fatalities in Russia.

German Foreign Minister Annalena Baerbock said it was suspicious that "a disgraced former confidant of Putin suddenly, literally falls from the sky two months after he attempted a mutiny".

Even influential pro-Kremlin figures, such as state television personality and Putin ally Margarita Simonyan, seemed to suggest that it could have been an assassination.

"Among the versions that are being discussed (about the crash) is that it was staged. But personally, I'm leaning towards the more obvious one," she said on social media.

Russia's aviation authority published the passenger list for the Embraer private jet late on Wednesday.