US intelligence believes that the head of PMC Wagner, Yevgeny Prigozhin, has long "been planning a major challenge to Russia’s military leadership," CNN reports, citing sources familiar with the intelligence.

At the same time, it is not known what the ultimate goal is, CNN writes.

Earlier this week, intelligence officials briefed Congressional leaders on Wagner's movements and "equipment build-up near Russia," the sources said.

“US and Western intelligence officials saw signs Prigozhin was making preparations for such a move, including by massing weapons and ammunition, one western intelligence official and another person familiar with the intelligence said,” the media outlet reports.
The sources said they believed Prigozhin's claims of a shortage of ammunition for operations in Ukraine were a deliberate deception "to help lay the groundwork for a potential military challenge to Russian leaders."

CNN also notes that US officials were baffled by the speed of the situation that unfolded on Friday night and escalated on Saturday, forcing senior officials to cancel planned international travel and call emergency government meetings.