Russian warlord Yevgeny Prigozhin claimed his forces were “blockading” Rostov and marching on Moscow on Saturday morning, as armed, masked men with tanks and armoured vehicles surrounded government buildings in the southern Russian city.

In what would mark the first coup attempt in Russia for three decades, Prigozhin appeared to have taken over a military headquarters in Rostov, where he was filmed ranting at a deputy defence minister and a senior general about his attempt to oust the army’s leadership.

The extraordinary scenes were part of what Prigozhin said was a “march of justice” against defence minister Sergei Shoigu and Valery Gerasimov, commander of Russia’s invasion forces. Prigozhin’s paramilitary group Wagner has been feuding with the two officials for months over the handling of the Ukraine invasion.

“We want [Gerasimov] and Shoigu. Until they’re here, we’ll stay, blockade Rostov and head to Moscow,” Prigozhin told deputy defence minister Yunus-Bek Yevkurov and Vladimir Alekseyev, deputy head of Russian military intelligence. “We are saving Russia.”

In another video posted shortly afterwards, Prigozhin said Wagner controlled “the military facilities of Rostov, including the airport,” but was not hindering operations in the invasion of Ukraine.

“We do it in such a way that the attack planes do not hit us, but the Ukrainians. The headquarters work normally, not a single officer is out of work. If they will tell you that Wagner hindered the work and that is why something fell down at the front — that is not the reason why something fell down there,” Prigozhin added.

“Huge areas have been lost, the number of fallen soldiers is three to four times higher than in the documents that are delivered up, and 10 times higher than what they say on TV.”

The scenes at the army command centre came after Prigozhin said Wagner had opened fire on Russian forces and shot down three army helicopters.

With Wagner’s months-long dispute with the army at boiling point, Russia’s security services treated his statements with unprecedented seriousness. The FSB, Russia’s main security service, on Friday accused Prigozhin of organising an armed uprising, while two senior generals who rarely speak in public urged Wagner’s fighters to stand down from a “state coup”.

Prigozhin’s gambit appeared to mark the collapse of a hybrid system in which a patchwork of competing security forces fought on Russia’s behalf in Ukraine, often at cross purposes. The chaos follows months of public infighting between Wagner and the army as Russia’s full-scale invasion of Ukraine continues to sputter.

Officials in Rostov, home to a big command centre overseeing President Vladimir Putin’s war in Ukraine, urged people to stay at home and avoid the town centre. Masked men set up positions outside Russia’s southern military headquarters and several other security services buildings, according to local site 161.ru and multiple videos posted on local social media.

It was not immediately clear whether all the men were Wagner fighters or part of Russia’s regular armed forces, though photographs on state newswire Tass suggested some of them were members of the paramilitary group.

Rostov’s governor Vasily Golubev wrote on social media that public transport routes would be changed “because of the current situation”, without explaining why.

Outside Rostov, there was little sign of Prigozhin’s forces, which he said numbered 25,000 men, or of any clashes with Russian forces.

There was no independent confirmation of any of Prigozhin’s statements, footage indicating Wagner had mustered such a force, or indication it had engaged in firefights with the army.

But a governor in central Russia said a highway to Moscow had been shut down north of Rostov, while officials in the capital said “anti-terrorist operations” were under way.

Dmitry Peskov, Kremlin spokesman, said Putin was receiving regular updates on the situation and had given unspecified orders to his security services. Neither Putin nor any other senior Russian official had made public comments on Prigozhin’s apparent uprising as of 7am local time on Saturday.