U.S. officials told media outlets on Thursday that they believe the plane presumed to be carrying mercenary leader Yevgeny Prigozhin was deliberately taken down, though there was some disagreement as to how exactly the plane was destroyed.
Russian air authorities have said Prigozhin, his right-hand man Dmitry Utkin, and eight other people were on the private plane that crashed with no survivors north of Moscow on Wednesday.
Two U.S. officials, speaking on the condition of anonymity, told Reuters that it was likely a surface-to-air missile originating from inside Russia shot down the plane.
The officials stressed that the information was still preliminary and under review, and did not rule out a change to the assessment.
The Wall Street Journal on Thursday reported a different theory: Officials told the outlet a bomb aboard the aircraft or some other sabotage caused the crash.
The New York Times reported a similar assessment from U.S. and Western officials, who said the leading theory is that an explosion on board the plane took it down. They said the explosion could have been caused by a bomb planted on the plane or by adulterated fuel.
It is not uncommon for there to be competing, even contradictory, intelligence views in the U.S. government in the hours and days after major international events.
A third U.S. official told Reuters that there were a number of theories and no definitive conclusion had been reached.
The crash came two months to the day after Prigozhin and his Wagner mercenaries staged a mutiny in which they took control of a southern city and advanced toward Moscow, shooting down a number of Russian Air Force planes and killing their pilots.
President Joe Biden on Wednesday said he was not surprised by reports that Prigozhin had died in a plane crash, adding that not much happens in Russia that President Vladimir Putin was not behind.
Putin on Thursday said he wished to express sincere condolences to the families of those who died in the crash and said it was necessary to await the outcome of the official investigation. Prigozhin, 62, head of the Wagner mercenary group, frequently criticized the Russian army top brass over what he said was its incompetent execution of the war in Ukraine.
The Embraer executive jet model that crashed in Russia had only recorded one accident in more than 20 years of service, and that was not related to mechanical failure.
While portraying it as a purely private commercial operation, the Kremlin has used Wagner to expand Russian influence on the continent in competition with Western powers such as France and the United States.
Prigozhin and a Russian company he controlled were indicted in 2018 and accused of funding a propaganda operation to meddle in the 2016 U.S. presidential election to sway it in favor of Republican candidate Donald Trump and to disparage rival Hillary Clinton.
(Reporting by Phil Stewart and Idrees AliEditing by Alistair Bell)