Prominent Russian nationalist Igor Girkin, who had publicly accused President Vladimir Putin and the army top brass of not pursuing the war in Ukraine harshly or effectively enough, was remanded in custody on Friday on charges of inciting extremism.
The arrest of a man the West regards as a war criminal suggests authorities have wearied of his criticism of what they call Russia's "special military operation", and perhaps of other loud nationalist voices who had appeared to have exceptional licence to deride the war effort.
It follows an abortive mutiny last month led by another outspoken critic, Yevgeny Prigozhin, boss of the Wagner mercenary force, who is still free but has sharply curtailed his own verbal attacks.
A Moscow court remanded Girkin, 52, in investigative custody until September 18 after he was seized by his ex-employer, the FSB state security service. The charge brought by prosecutors carries a maximum sentence of five years in prison, state news agencies TASS and RIA reported.
Girkin denies the accusations against him - reported to centre on two outbursts he posted on the Telegram app - and is refusing to cooperate with investigators, the Interfax news agency reported.
Alexander Molokhov, his lawyer, told reporters that he would appeal the decision to remand his client in custody. The lawyer complained he had not been given enough time to familiarise himself with the charges against Girkin, which he said amounted to a procedural violation.
Britain's defence ministry, in a regular intelligence update on Saturday, said the arrest was "likely to infuriate fellow members of the military blogger community, who largely see Girkin as an astute military analyst and patriot".
Girkin, a former FSB officer and battlefield commander also known as Igor Strelkov, helped Russia to annex Crimea in 2014 and, soon after, to organise pro-Russian militias who wrested part of eastern Ukraine out of Kyiv's control - events that started Russia's war on Ukraine.
Ukrainian officials and Western human rights groups accused him of committing war crimes there, something he denied.
He was handed a life sentence in absentia by a Dutch court in 2022 for his alleged role in the shooting down of Malaysia Airlines flight MH17 over eastern Ukraine in 2014, with the loss of 298 passengers and crew. He denied wrongdoing at the time.
In footage from court posted by the popular Telegram channel Shot, Girkin stood almost motionless in a glass cage, with his arms folded, staring straight ahead.
Police detained at least two of his supporters outside the court building, a Reuters reporter said. One of them had been repeating Girkin’s own criticisms of the war in Ukraine and a woman who had been holding a sign saying “The Truth is Power”.