A Russian court on Tuesday sentenced top human rights campaigner Oleg Orlov to two and a half years in jail for denouncing Russia's assault on Ukraine.

The 70-year-old, a key figure of the Nobel Prize-winning Memorial group, is the latest target of Kremlin repression, which has intensified since the offensive in Ukraine.

"The court has determined Orlov's guilt and orders a sentence of two years and six months... in a general regime penal colony," the judge said.

As the judge read the verdict, the bespectacled, white-haired activist winked at his wife, fellow activist Tatyana.

He was taken into custody in the courtroom and asked Tatyana to come over.

"Tanya, you promised me!" he told her as she appeared to tear up.

Around 200 supporters were waiting in the corridor outside the courtroom to bid him goodbye.

Orlov had told AFP in a recent interview that he held no illusions on the outcome of the trial.

Orlov was accused of discrediting the Russian army in a column written for the French online publication Mediapart, and fined in October after a first trial.

The fine was a relatively lenient punishment and prosecutors called for a new trial.

Even as other campaigners fled the growing repression, Orlov remained in Russia, where he said he was "more useful" than abroad.

He told AFP that his career spent working on the historical memory of Soviet crimes and rights abuses in modern Russia -- especially in the North Caucasus -- gave him no choice but to also campaign against the Ukraine offensive.

Memorial established itself as a key pillar of Russian civil society by preserving the memory of victims of communist repression and by campaigning against rights violations.

The organisation was officially disbanded by Russian authorities in late 2021 and it won the Nobel Peace Prize in 2022 alongside a leading Ukrainian rights group and a veteran Belarusian activist.