A participant of an anti-corruption rally has been handed a 2.5-year-prison sentence, Russian media reported on Thursday.

Stanislav Zimovets, a 32-year-old Chechen War veteran, was convicted of throwing a rock at a National Guard officer during an unsanctioned anti-corruption protest organized by opposition politician Alexei Navalny in central Moscow on March 26.

Prosecutors had asked for a three-year sentence against Zimovets, presenting other officers as witnesses and video footage purportedly proving Zimovets’ blame.

Zimovets initially plead guilty, but later withdrew his statement, saying that he had been manipulated into a forced confession.

He admitted to throwing the brick fragment but said he had not deliberately targeted the officer. The defense also said footage failed to prove the brick fragment had actually hit anyone.

The anti-corruption protest on March 26 drew thousands to the streets in rare nationwide anti-government protests.

Hundreds of people were arrested, including a number of Russian and foreign journalists. Zimovets is the third person to be given a prison sentence, as of July 20.