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.

His arrest earlier in the day by his ex-employer, the FSB state security service, 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 license 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.

The charge brought by FSB prosecutors carries a maximum sentence of five years in prison, state news agencies TASS and RIA Novosti reported. The RBC news site said the Meshchansky district court in Moscow had remanded Girkin, 52, in investigative custody until Sept. 18.

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.

He was also 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.

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.