Russian intelligence authorities have accused Russian mercenary chief Yevgeny Prigozhin of calling for “armed mutiny” against the state, after the warlord vowed to take revenge on Russian defense officials for an alleged attack on his men.

“The statements that are being spread on behalf of Yevgeny Prigozhin are absolutely unfounded,” Russia’s National Anti-Terrorism Committee said Friday, per state-run TASS. “In connection with these statements, the Federal Security Service of Russia has started an investigation into a call for an armed mutiny. We demand that unlawful actions be stopped immediately.”

Prigozhin has vowed to take revenge for alleged “missile strikes at our rear camps” by regular Russian forces, in a seeming eruption of his long-running dispute with Russian Defense Minister Sergey Shoigu. The warlord made a point of stipulating that “presidential authority” and Russia’s internal security services “will continue operating as before,” but the outburst drew an ominous statement from the Kremlin.

“President Putin has been briefed on all events around Prigozhin,” said Kremlin press secretary Dmitry Peskov, according to an unofficial translation of state-run TASS. "The necessary measures are being taken.”

Prigozhin’s public statements stirred Igor Girkin, another ultranationalist critic of the Kremlin who has also denounced the Wagner Group chief, to speculate that “a coup attempt is underway” — although he acknowledged the possibility that Prigozhin has a different scheme in mind.

“If this isn't a fake (which it can be), the military coup has started,” Girkin wrote on social media, per the War Translated project. “But if it isn't a fake, then the situation with the face-off between MoD and Wagner is out of control and needs immediate involvement by the president.”