Yevgeny Prigozhin, the chief of the Russian Wagner mercenary group, was presumably dead when a private jet carrying him and nine others crashed over Russia Wednesday, emergency officials said.

Russia’s state news agency Tass cited emergency officials as saying that the plane carried three pilots and seven passengers. It was not initially clear if Prigozhin was among those on board, though Russia’s civilian aviation regulator, Rosaviatsia, said he was on the passenger list.

The plane was en route from Moscow to St. Petersburg and went down in the Tver region, more than 100 kilometers (60 miles) north of the capital. Authorities are investigating.

Flight tracking data reviewed by The Associated Press shows a private jet registered to Wagner that Prigozhin had used previously took off from Moscow on Wednesday evening and its transponder signal disappeared minutes later.

The signal was lost in a rural region where there are no nearby airfields where the jet could have landed safely.

Prigozhin, whose private military force Wagner fought alongside Russia's regular army in Ukraine, mounted a short-lived armed mutiny against Russia's military leadership in late June. The Kremlin said he would be exiled to Belarus, and his fighters would either retire, follow him there, or join the Russian military.

Shortly after that, Wagner fighters set up camp in Belarus, but Prigozhin's plane, according to media reports, was flying back and forth between Belarus and Russia.

This week, Prigozhin posted his first recruitment video since the mutiny, saying that Wagner is conducting reconnaissance and search activities, and "making Russia even greater on all continents, and Africa even more free."