Russian officials say the founder of the Wagner mercenary group, Yevgeny Prigozhin, may have been on board a plane that crashed. They say a list of the 10 passengers on the plane included his name. A social media channel linked to him says he was killed.
The private plane was reportedly traveling from Moscow to St. Petersburg and crashed northwest of the capital.
The Reuters news agency released video said to be of the plane falling. It includes the voice of an eyewitness saying they heard "two explosions" before the crash.
Prigozhin built a private paramilitary force that sent tens of thousands of fighters to Ukraine on Russia's behalf. However, he grew frustrated with military leaders and led a mutiny against them in June before backing down.
There were questions as to his whereabouts, but on Monday he posted a video on social media saying that he was somewhere in Africa.
Prigozhin was believed to have close ties to the former commander of Russian forces in Ukraine, Sergei Surovikin, who had moved on to lead aerospace forces. Surovikin was said to have known about the Wagner mutiny beforehand. State-run media says he has been dismissed.