Senior American national security officials had indications as early as Wednesday that Yevgeny Prigozhin, the leader of the Wagner Group, was preparing to take military action against senior Russian defense officials, according to officials briefed on the intelligence.
The information suggests that the United States had at least some warning of impending chaos in Russia, just as it warned in late 2021 that Vladimir V. Putin was planning to invade Ukraine.
In this case, the information was considered both solid and alarming because of the possibility that a major nuclear-armed rival of the United States could descend into chaos.
While it is not clear exactly when the United States first learned of the plot, intelligence officials conducted briefings on Wednesday with the administration and defense officials. On Thursday, as additional confirmation of the plot came in, intelligence officials informed a narrow group of congressional leaders, according to officials familiar with the briefings who spoke on condition of anonymity because they were not authorized to speak publicly. By Friday night, Prigozhin had dramatically escalated his feud, launching a march on Moscow that the Russian government described as an attempted coup. On Saturday, he called his fighters off and agreed to flee to Belarus after a day of tumult.
For months, intelligence officials have tracked rising tensions between Mr. Prigozhin and leaders of Russia’s defense ministry, including Sergei K. Shoigu, the minister of defense.
Intelligence reports released as part of the Discord leaks showed that the United States had intercepted communications between senior Russian military leaders debating how to handle Mr. Prigozhin’s constant demands for more ammunition.
Most of those tensions played out in public, as the leader of the mercenary military group used interviews and Telegram posts to berate Mr. Shoigu and Gen. Valery Gerasimov, the chief of the general staff of the Russian armed forces, calling them incompetent and charging that they misled Mr. Putin about the progress of the war with Ukraine.
But it was only in recent days that intelligence officials got the initial warnings that Mr. Prigozhin might take action.
Officials said that intelligence agencies did not know what the results of Mr. Prigozhin taking military action would be, but they were immediately worried about how it might affect the control of Russia’s arsenal of nuclear weapons. President Biden, speaking last October, talked of the dangers that Mr. Putin would pose if he felt cornered and said the U.S. was looking for “off ramps” for Mr. Putin.
CNN earlier reported that the U.S. briefed congressional leaders about their concerns that Mr. Prigozhin was preparing to challenge Russia’s military leadership.
Since Mr. Prigozhin took action on Friday, American officials have been locked down, saying little publicly about his intentions or what they knew about events on the ground. Officials have been wary, both because events were moving fast and because they did not want to give Mr. Putin any excuse to blame the west for Mr. Prigozhin’s actions. But several officials said they fully expected that Mr. Putin would eventually say the uprising was the result of a foreign plot.