Russian strongman Yevgeny Prigozhin has been charged with organising an armed uprising after threatening to attack Russian forces in retaliation for what he claimed was an air strike against his own paramilitaries.

Prigozhin, founder of the notorious Wagner mercenary group, said on Friday that a “huge number” of fighters had been killed in the alleged air strike and that Wagner would “respond to this evildoing” by launching a “march of justice” against Russia’s army, in his most vitriolic tirade against his country’s military leadership to date.

Russia’s defence ministry dismissed Prigozhin’s claims of an air strike as an “information provocation”, and the FSB, Russia’s main security service, “launched a criminal case over calls for an armed uprising”, Russia’s national anti-terrorism committee said, according to state newswire Ria Novosti.

The FSB later added: “Prigozhin’s statements and actions amount to calls for the start of an armed civil conflict on Russian territory and are a ‘stab in the back’ for Russian servicemen fighting pro-fascist Ukrainian forces,” according to Ria Novosti.

Prigozhin had created “the risk of escalating the confrontation”, it added, urging people “not to make irrevocable mistakes, to stop all uses of force against the Russian people, not to carry out Prigozhin’s criminal and treasonous orders, and take steps to detain him”.

The Russian prosecutor-general’s office confirmed Prigozhin had been charged with “organising an armed uprising”, which carries a sentence of 12 to 20 years in prison. It said his “actions will receive appropriate legal assessment”.

Dmitry Peskov, Vladimir Putin’s spokesperson, said the Russian leader was aware of Prigozhin’s statements and that “all essential measures are being taken”, according to Ria Novosti.

The threat came just hours after Prigozhin in a separate tirade accused the Russian military of deceiving Putin into invading Ukraine, and the videos together signalled a new, more aggressive phase of the strongman’s offensive against the Kremlin’s war planners.

Prigozhin, who emerged as one of the crucial leaders of Russia’s invasion since Wagner took a leading role on the front lines, has been embroiled in a feud for several months with defence minister Sergei Shoigu, who Prigozhin has accused of sabotaging the war effort together with Valery Gerasimov, chief of Russia’s general staff.

He claimed Shoigu had ordered the alleged air strike in secret, then “ran away like a bitch to avoid explaining why he sent helicopters to destroy our boys”.

“The evil brought by the country’s military leadership must be stopped. Those who destroyed our boys today and ruined the lives of many tens of thousands of our soldiers will be punished,” Prigozhin said.

Without explaining what specific steps Wagner would take, Prigozhin added: “I ask that nobody resist. We will consider everyone who resists to be a threat and destroy them at once.”

He claimed “presidential power, the government, [and] other structures” would work as normal, while Wagner “deals with the people destroying Russian soldiers and return to the front”.

In the earlier video on Friday, Prigozhin said Russia’s defence ministry concocted false pretences to trick Putin into invading Ukraine and said Moscow could have avoided the war entirely.

Prigozhin claimed Russia had faced no immediate threat from Ukraine when Putin began his full-scale invasion last year and accused the army’s top brass of deceiving the president for their own personal gain.

Prigozhin’s regular diatribes, in which he claims Russia runs the risk of losing the war after Ukraine began a counteroffensive earlier this month, had indicated elite infighting was getting fiercer as Moscow’s war effort continues to struggle.

Though Prigozhin notably refrained from criticising Putin personally and has backed the war’s goals, the video was the first time he publicly questioned Russia’s rationale for the full-scale invasion.

He claimed Shoigu had convinced Putin the war was necessary so “a bunch of bastards could rule the roost and show off about what a strong army they have”, then botched the invasion through “incompetent planning”.

In a country where “discrediting the armed forces” is punishable with up to 15 years in prison, Prigozhin, who has known Putin since their days in St Petersburg in the early 1990s, was widely believed to have the Russian president’s approval for his attacks on the army.

Prigozhin’s rants on the war’s failures notably absolved Putin himself or the FSB security service, which played a much more prominent role in planning the invasion than the army.

Putin admitted earlier this month that he had personally pardoned convicts so they could be released to fight in Ukraine — a recruitment technique pioneered by Prigozhin when he raised a prisoner army to fight in the “meat grinder” of Bakhmut in eastern Ukraine.

After Russia captured the city last month, however, Putin backed Shoigu’s efforts to bring irregular units such as Wagner under the army’s control. Since then, Wagner’s troops have been absent from the front lines, and Prigozhin had cast doubt on whether they will return at all.

He said Russia’s army continued to lie to Putin about the success of Ukraine’s counteroffensive: “We’ll only face the truth when [ . . . ] this bunch of bastards realise they have already pissed away a huge piece of territory and declare they are regrouping somewhere better.”