The aborted mutiny by Russia's Wagner mercenary group at the weekend demonstrated the scale of the Kremlin's strategic mistake in waging war on Ukraine, NATO Secretary-General Jens Stoltenberg said on Monday, June 26. Wagner fighters halted a rapid advance on Moscow on Sunday, withdrawing from the seized southern Russian city of Rostov and heading back to their bases late on Saturday under a deal that guaranteed their safety, in Putin's biggest threat to his presidency in two decades. Wagner commander, Yevgeny Prigozhin, agreed to move to Belarus under the deal mediated by Belarusian President Alexander Lukashenko, the Kremlin said. But the transatlantic military alliance, NATO says the chaos in Russia shows that invading Ukraine last year was a strategic mistake by Putin."The events over the weekend are an internal Russian matter, and yet another demonstration of the big strategic mistake that President (Vladimir) Putin made with his illegal annexation of Crimea and the war against Ukraine," Stoltenberg told reporters on a visit to Lithuania's capital Vilnius. Confusion over the weekend's extraordinary events has left Western governments groping for answers to what could happen next in the country with the world's largest nuclear arsenal - and to its war on Ukraine. Stoltenberg said NATO was monitoring the situation in Belarus and, again, condemned Moscow's announcement to deploy nuclear weapons there. "We don't see any indication that Russia is preparing to use nuclear weapons but NATO remains vigilant," he said, adding NATO's deterrence was strong enough to keep its people safe in a "more dangerous world."