Russian helicopters fire on rebel mercenary convoy heading toward Moscow

Russian military helicopters opened fire on Saturday afternoon on a convoy of rebel mercenaries already more than halfway toward Moscow in a lightning advance after claiming to have seized a southern city overnight.

President Vladimir Putin vowed to crush an armed mutiny he compared to Russia's Civil War a century ago.

Fighters from Yevgeny Prigozhin's Wagner Group private militia appeared to be in control of Rostov-on-Don, a city of more than a million people close to the border with Ukraine, and were rapidly advancing northward through western Russia.

A Reuters journalist saw army helicopters open fire at an armed Wagner Group column that was advancing past the city of Voronezh with troop carriers and at least one tank on a flatbed truck. The city is more than halfway along the 1,100-kilometre  highway from Rostov to Moscow.

Prigozhin, whose private army fought the bloodiest battles in Ukraine even as he feuded for months with the top brass, said he had captured the headquarters of Russia's Southern Military District in Rostov after leading his forces into Russia from Ukraine.

In Rostov, which serves as the main rear logistical hub for Russia's entire invasion force, residents milled about, filming on mobile phones, as Wagner fighters in armoured vehicles and battle tanks took up positions. One tank was wedged between stucco buildings with posters advertising the circus. Another had "Siberia" daubed in red paint across the front, a clear statement of intent to sweep across the breadth of Russia.

The dramatic turn, with many details unclear, looked like the biggest domestic crisis Putin has faced since he ordered a full-scale invasion of Ukraine — which he called a "special military operation" — in February 2022. Britain's Defence Ministry called it "the most significant challenge to the Russian state in recent times." 

In a televised address, Putin said that "excessive ambitions and vested interests have led to treason," and called the mutiny a "stab in the back."

"It is a blow to Russia, to our people. And our actions to defend the Fatherland against such a threat will be harsh," he said.

"All those who deliberately stepped on the path of betrayal, who prepared an armed insurrection, who took the path of blackmail and terrorist methods, will suffer inevitable punishment, will answer both to the law and to our people."

Prigozhin rebutted that he and his forces would not turn themselves in as Putin demanded.

"The president makes a deep mistake when he talks about treason. We are patriots of our Motherland, we fought and are fighting for it," Prigozhin said in an audio message.

"Nobody is going to turn themselves in and confess at the order of the president, the FSB [security service] or anyone else. Because we don't want the country to continue to live any longer in corruption, deceit and bureaucracy."

Prigozhin has demanded that Defence Minister Sergei Shoigu and Valery Gerasimov, chief of the General Staff, whom he has pledged to oust over what he says is their disastrous leadership of the war against Ukraine, come to see him in Rostov, a city near the Ukrainian border that he said he had seized control of.