Russian anti-Putin campaigner Alexei Navalny has denounced his detention as “demonstratively illegal” in an appeal hearing via video link.

A judge heard, and then rejected, his appeal against detention for 30 days. He was arrested on 17 January for not complying with a suspended sentence.

He told the judge “this is all massively, demonstratively illegal”.

Police have arrested some of his top aides, including lawyer Lyubov Sobol and his brother Oleg.

The latest arrests are connected with alleged violations by Navalny supporters, who rallied in their thousands across Russia last Saturday.

Mr Navalny, Russia’s most prominent opposition leader, complained that he had not been allowed to speak to his lawyers in private since his arrest.

He has been detained since 17 January, when he flew back to Moscow from Berlin, where he had been recovering from a near-fatal nerve agent attack in Russia last August.

He accuses President Vladimir Putin of running an administration full of “thieves”.

He blamed his treatment on “those who want to shut me up – to scare me and everyone else.

“You want to show you’re the bosses of this country. But you are not. You have the power now, but that’s not eternal.”

He spent months recovering from the nerve agent attack which nearly killed him – for which he blamed agents of Mr Putin.

The Kremlin denies involvement. The opposition politician’s allegations have, however, been backed up by reports from investigative journalists.