The death toll from a Russian missile strike on a restaurant in eastern Ukraine rose to eight on Wednesday, as Kyiv played down the effect of a brief mutiny by the head of the Wagner mercenary group on the conflict.

The blast at the Ria Pizza restaurant also killed three children and wounded at least 56 at the eatery, popular with both soldiers and journalists in the town of Kramatorsk, one of the largest still under Ukrainian control in the east.

Days after the aborted rebellion of Wagner head Yevgeny Prigozhin, widely seen as the biggest threat to Kremlin authority in decades, Kyiv said the mutiny's influence on fighting was minimal.

"Unfortunately, Prigozhin gave up too quickly. So there was no time for this demoralising effect to penetrate Russian trenches," Ukrainian Foreign Minister Dmytro Kuleba told CNN in a video published Wednesday.

As Belarus welcomed Prigozhin into exile on Tuesday, Russian President Vladimir Putin moved to shore up his authority by thanking regular troops for averting a civil war.

But as Moscow announced preparations to disarm Wagner fighters, Putin's arch-foe, jailed Kremlin critic Alexei Navalny, launched a stinging attack on the president in his first comments since the aborted mutiny by the paramilitaries.

"There is no bigger threat to Russia than Putin's regime," Navalny said on social media. 

"Putin's regime is so dangerous to the country that even its inevitable demise will create the threat of civil war," he wrote.

In the Hague, NATO chief Jens Stoltenberg said it was still too early to draw conclusions from the move to Belarus of Prigozhin and, likely, some of his forces, but he vowed that the alliance was ready to defend its members.

"What is absolutely clear is that we have sent a clear message to Moscow and to Minsk that NATO is there to protect every ally and every inch of NATO territory," Stoltenberg said.

- 'Stopped civil war' -

Putin's supporters, however, insisted that his rule was not weakened by the revolt.

Asked whether Putin's power was diminished by the sight of Wagner's rebel mercenaries seizing a military HQ, advancing on Moscow and shooting down military aircraft along the way, Kremlin spokesman Dmitry Peskov accused political commentators of exaggerating, adding that: "We don't agree."

Putin himself attempted to portray the dramatic events at the weekend as a victory for the Russian army.

"You de facto stopped civil war," Putin told troops from the defence ministry, National Guard, FSB security service and interior ministry gathered in a Kremlin courtyard to hold a minute's silence for airmen slain by Wagner.

- Private army -

Prigozhin, a former Kremlin ally and catering contractor who built Russia's most powerful private army, has boasted -- with some support from news footage -- that his men were cheered by civilians during his short-lived revolt.

But Putin insisted that Wagner's ordinary fighters had seen that "the army and the people were not with them".

In a separate meeting with defence officials, Putin confirmed that Wagner was wholly funded by the Russian federal budget, despite operating as an independent company, adding that in the past year alone since the assault on Ukraine, Moscow had paid the group 86.262 billion rubles (about $1 billion) in salaries.

The feud between Wagner and the army had escalated for months, with Prigozhin making increasingly scathing statements against the generals' handling of the offensive in Ukraine, blaming them for thousands of Russian losses.

Russian officials have been trying to put the crisis behind them for three days, with the FSB dropping charges against rank-and-file Wagner troops and the military preparing to disarm the group.

But, questions remain over how the Kremlin allowed the violence of its operation in Ukraine to spill back into Russia.

Belarus strongman Alexander Lukashenko is seeking credit for stepping in to mediate Wagner's U-turn on the road to Moscow, and on Tuesday he criticised Russia's handling of the issue.

- 'We could waste him' -

Talking to his own military officials, Lukashenko said that Prigozhin was arriving in Belarus on Tuesday, and revealed that he had urged Putin not to kill the rogue mercenary.

"I said to Putin: we could waste him, no problem. If not on the first try, then on the second. I told him: don't do this," Lukashenko said, according to state media.

In his address, Putin also stressed that the revolt had not forced Russia to withdraw any of its units from Ukraine, where fighting continued as Kyiv's brigades pursued their counteroffensive in their nation's east and south.

The bloody conflict is now 16 months old, with mass casualties on both sides and a rising civilian toll.

Also on Tuesday, the United Nations Human Rights Monitoring Mission in Ukraine said it had evidence that Russian troops had summarily executed at least 77 detained civilians. 

"It is a war crime... it's also a gross violation of international human rights law," said Matilda Bogner, head of the mission.

Meanwhile, the United States announced a new $500 million tranche of arms to bolster Ukraine's mounting counteroffensive, including armoured vehicles, precision munitions and mine-clearing equipment.

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