Russia has recently arrested several senior military and defence figures over alleged fraud and bribe-taking, more than two years into Moscow's offensive in Ukraine.

Major-General Ivan Popov was released from behind bars Monday after being arrested in May on suspicion of large-scale fraud, punishable by up to 10 years in prison.

The decision to release Popov from custody was taken by the Number 235 military court behind closed doors on the request of investigators, court spokeswoman Alyona Pligina told AFP.

Popov, wearing a grey T-shirt, smiled as he left the court accompanied by his lawyers and supporters, according to footage on RBK news channel.

The Investigative Committee had requested Popov be moved to house arrest in May, citing information on the defendant and "other circumstances that came to light" during the investigation.

Investigators said Ivanov is accused over misappropriation of more than 1,700 tonnes of metal acquired by Russian occupying authorities to reinforce defences in Ukraine's southern Zaporizhzhia region.

The rolled metal was worth over 130 mn rubles ($1.5 mn), according to the Investigative Committee, which probes major crimes.

Popov was commander of Russia's 58th Combined Arms Army fighting in Ukraine until he was removed from his post last summer.

He released an audio message in July last year, saying he had been dismissed after drawing the military leadership's attention to "mass deaths and injuries" among Russian soldiers in Ukraine.

His arrest prompted criticism from Russia's influential military bloggers, who praised Popov as a hard-working and respected commander.

In April this year, Russia detained a deputy defence minister, Timur Ivanov, on suspicion of taking large bribes.

President Vladimir Putin in May removed long-serving defence minister Sergei Shoigu in a major shake-up of Russia's military leadership

Later in May, in what Russian media has called a "purge" of top brass, another senior defence ministry official, Lieutenant-General Yuri Kuznetsov, and Vadim Shamarin, the deputy head of Russia's General Staff, were detained on bribery charges.