A Jewish politician in Russia has been sent to prison over comments comparing the Nazi and Soviet regimes, in a move that has raised concerns of a growing regime crackdown.

Leonid Grozman was sentenced by a Moscow district court to 15 days’ imprisonment over a nine-year-old article in which the opposition leader said the Soviet regime was worse than Adolf Hitler’s government.

It marks the second time the text has got Mr Grozman into trouble. Earlier this year the civil society activist was handed down an initial 15-day sentence. 

Russian-language news website Meduza reported that Mr Grozman wrote: “Hitler was an absolute evil, but Stalin was even worse. The SS were criminals, but the NKVD [the secret police] were even more terrible, because the Chekists murdered their own.

“Hitler unleashed a war against humanity; the communists declared total war against their own people.”

In a statement posted online by his daughter, Mr Grozman said: “They arrested me again. I waited for it and decided from the very beginning that I would have to sit not for 15 days, but for a long time, maybe until I die…

“I am morally prepared for prison. I am not guilty of anything, neither to the people nor to the country. I was just exercising my natural right to speak the truth about our lives and our authorities. 

“I was just doing my civil duty – as much as I could to fight against this inhuman system that condemns Russia and the world to death. I don't regret a word said. 

“I don't regret going back when I was declared a foreign agent. I don’t regret a single thing. And I believe that this sea will pass! Don't lose your hope ! Keep your hands up!”

In 2021, a law criminalising comparisons between the Nazi and Soviet regimes was adopted.

Mr Grozman has previously been detained over his Israeli citizenship.

In July, police arrested him over his alleged failure to inform the authorities swiftly enough about his dual nationality.

Mr Grozman has previously criticised Vladimir Putin’s government over the war in Ukraine. 

Earlier this year he posted on messaging app Telegram, Reuters reported, to say: "For those who want and can protest – be careful, remember that what was almost free yesterday – a small fine –can cost freedom today.

“Only if you understand what you will have to pay with – go ahead, and may God help you. Everyone else – do not give up."

In June, he was listed by the Russian government as a “foreign agent”, meaning he stands accused of taking money from or working for an organisation outside Russia.

From 2008 to 2011 Mr Grozman was the chairman of Just Cause, a centre-right political party, and he now chairs Union of Right Forces, a group which brought together free-market reformers.

The organisation’s co-founder, Boris Nemtsov, was shot dead outside the Kremlin in 2015.