By Andrew Osborn and Kevin Liffey
LONDON (Reuters) - Russia accused mercenary chief Yevgeny Prigozhin of armed mutiny on Friday after he alleged, without providing evidence, that the military leadership had killed a huge number of his fighters in an air strike and vowed to punish them.
The standoff, many of whose details remained unclear, looked like the biggest domestic crisis President Vladimir Putin has faced since he ordered a full-scale invasion of Ukraine - something he called a "special military operation" - in February last year.
As the standoff between Prigozhin, founder of the Wagner mercenary force, and the defence ministry appeared to come to a head, the ministry issued a statement saying Prigozhin's accusations were "not true and are an informational provocation".
Prigozhin said his actions were not a military coup. But in a frenzied series of audio messages, in which the sound of his voice sometimes varied and could not be independently verified, he appeared to suggest that 25,000 fighters were en route to oust the leaders of the defence establishment in Moscow.
He said: "Those who destroyed our lads, who destroyed the lives of many tens of thousands of Russian soldiers, will be punished. I ask that no one offer resistance ...
"There are 25,000 of us and we are going to figure out why chaos is happening in the country," he said, promising to tackle any checkpoints or air forces that got in Wagner's way.
At about 2 a.m. on Saturday morning, Moscow time (2300 GMT), Prigozhin issued a new message saying his forces had crossed the border from Ukraine, and were in the southern Russian city of Rostov.
He said they were ready to "go all the way" against the top brass, and to destroy anyone who stood in their way.
At around the same time, the state news agency TASS quoted Kremlin spokesman Dmitry Peskov as saying all Russia's main security services were reporting to Putin "round the clock" on the fulfilment of his orders with respect to Prigozhin.
Security was being tightened in Moscow, TASS said, focusing on what it called the capital's most important government sites and infrastructure.
Earlier on Friday, Prigozhin had appeared to cross a new line in his increasingly vitriolic feud with the ministry, saying that the Kremlin's rationale for invading Ukraine was based on lies concocted by the army's top brass.
The FSB domestic security service said it had opened a criminal case against him for calling for an armed mutiny, a crime punishable with a jail term of up to 20 years.
"Prigozhin's statements are in fact calls for the start of an armed civil conflict on Russian territory and his actions are a 'stab in the back' of Russian servicemen fighting pro-fascist Ukrainian forces," the FSB said.
"We urge the ... fighters not to make irreparable mistakes, to stop any forcible actions against the Russian people, not to carry out the criminal and traitorous orders of Prigozhin, to take measures to detain him."
GENERALS URGE PRIGOZHIN TO BACK DOWN
Army Lieutenant-General Vladimir Alekseyev issued a video appeal asking Prigozhin to reconsider his actions.
"Only the president has the right to appoint the top leadership of the armed forces, and you are trying to encroach on his authority," he said.
Army General Sergei Surovikin, the deputy commander of Russian forces in Ukraine whom Prigozhin has praised in the past, in a separate video said that "the enemy is just waiting for our internal political situation to deteriorate".
"Before it is too late ... you must submit to the will and order of the people's president of the Russian Federation. Stop the columns and return them to their permanent bases," he said.
Prigozhin, whose men spearheaded the capture of the Ukrainian city of Bakhmut last month, has for months been openly accusing Defence Minister Sergei Shoigu and Russia's top general, Valery Gerasimov, of rank incompetence and of denying Wagner ammunition and support.
An unverified video posted on a Telegram channel close to Wagner showed the purported scene of an air strike against Wagner forces. It showed a forest where small fires were burning and trees appeared to have been broken by force. There appeared to be one body, but no more direct evidence of any attack.
It carried the caption: "A missile attack was launched on the camps of PMC (Private Military Company) Wagner. Many victims. According to eyewitnesses, the strike was delivered from the rear, that is, it was delivered by the military of the Russian Ministry of Defence."
Prigozhin has tried to exploit Wagner's battlefield success, achieved at enormous human cost, to publicly berate Moscow with seeming impunity, while carefully avoiding criticism of Putin.
But on Friday he for the first time dismissed Putin's core justifications for invading Ukraine on Feb. 24 last year, something for which many Russians have been fined or jailed.
"The war was needed ... so that Shoigu could become a marshal ... so that he could get a second 'Hero' [of Russia] medal," Prigozhin said in a video clip. "The war wasn't needed to demilitarise or denazify Ukraine."
Marat Gabidullin, a former Wagner commander who moved to France when Russia invaded Ukraine, told Reuters that Wagner's fighters were likely to stand with Prigozhin.
"We have looked down on the army for a long time ... Of course they support him, he is their leader," he said.
"They won't hesitate (to fight the army), if anyone gets in their way."
(Reporting by Reuters; Writing by Andrew Osborn and Kevin Liffey; Editing by Daniel Wallis)
