A Moscow court on Monday overturned a prison sentence for actor Pavel Ustinov, giving him instead a one-year suspended sentence, in a case that has sparked protests and a major solidarity campaign.

Ustinov, 23, was this month sentenced to three-and-a-half years in prison for violence against police at an opposition protest, despite his insistence he was simply a bystander.

A judge at the Moscow City Court said on Monday the ruling by Moscow's Tverskoi district court should be changed, an AFP correspondent said.

Around 25,000 people took part in an authorised opposition rally in Moscow on Sunday in support of those detained at earlier anti-government protests, according to an independent monitor.

Ustinov's supporters were outraged by his conviction, saying he is innocent. He and his defence lawyers said they were still not happy with the latest ruling and would appeal again.

"I did not commit any crime," Ustinov told reporters.

He insisted that members of the national guard acted unlawfully by accusing him of committing a crime.

Ustinov was found guilty after one of the officers accused him of causing a sprained shoulder.

High-profile lawyer Anatoly Kucherena, who has represented fugitive US whistleblower Edward Snowden and has taken up Ustinov's case, said the court's previous ruling "was not based on a single piece of evidence."

'Spitting in our face'

The actor's mother, Tatyana Ustinova, said it was "God's miracle" that Ustinov was freed at all.

But she added that even the suspended sentence meant her actor son may encounter problems in his line of work.

"Who will take the risk of inviting him?" she said.

Ustinov's conviction sparked a major solidarity campaign involving supporters ranging from film stars to priests to teachers.

Hundreds of people have demonstrated in Ustinov's support outside President Vladimir Putin's administration.

Ustinov's case caused particular outrage because the court initially refused to consider video footage from the scene that showed police in an apparently unprovoked attack on the actor.

During Monday's appeal, the court took into account the footage showing Ustinov standing with a phone in his hand near a metro station.

Ustinov was freed last week pending his appeal hearing.

He was released after prosecutors suddenly asked a court to give Ustinov a non-custodial sentence, saying his punishment was too harsh.

The apparent climbdown came after a harsh crackdown on the anti-government protests that has seen six people sentenced to jail terms of between two and four years.

Investigators backed down in several other cases, announcing that the mass unrest charges had been dropped against several men.

Over the summer, tens of thousands of people took to the streets of Moscow after authorities refused to allow prominent opposition candidates to stand for the city parliament in September 8 elections.

Around 60,000 people rallied in Moscow at the peak of the demonstrations in August but the new wave of protests has since lost momentum.

"After everything that happened, the 'court' of scumbags still sentenced Ustinov," fumed journalist and documentary filmmaker Andrei Loshak.

He said the actor had not been cleared of the charges because not enough people had taken to the streets on Sunday.

"Civil society is weak, they can continue spitting in our face."

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