Prime Minister Rishi Sunak said he is in touch with allies about the armed rebellion led by the Wagner mercenary group in Russia, which UK defence officials have described as "the most significant challenge" to the Kremlin in recent times.
President Vladimir Putin called the actions of the private military company a "betrayal" and vowed to defend Russia, after mercenary chief, Yevgeny Prigozhin, vowed to topple Moscow's military leadership.
