Girkin, who is also known as Igor Strelkov, helped Russia annex Crimea in 2014 and then organise pro-Russian militias in eastern Ukraine.

A former Federal Security Service (FSB) officer, he said earlier this year that he was entering politics and has been increasingly critical of President Vladimir Putin and Defence Minister Sergei Shoigu over what he has called the incompetent way Moscow is running what it calls its “special military operation” in Ukraine.

In a message posted on Girkin’s official Telegram account, his wife, Miroslava Reginskaya, said:

“Today, at about 11.30, representatives of the Investigative Committee came to our house. I was not at home. Soon, according to the concierge, they took my husband out by his arms and in an unknown direction.”

She said friends had told her that Girkin had been charged with extremism.

“I do not know anything about my husband’s whereabouts, he has not contacted me,” she said.

There was no immediate comment from the authorities.