Russian police seized a protest artist's work in a raid on an anti-war exhibition in Saint Petersburg on Wednesday, organisers said.

It comes as the Kremlin ramps up its crackdown on opposition to its Ukraine offensive, and just a day after the show opened.

Elena Osipova, 77, was showcasing around 20 works at a branch of the liberal Yabloko party in Russia's second city.

The party said police descended on the venue claiming there was a bomb threat.

No explosives were found, but officers “discovered graphic images drawn on canvas and carboard on the walls, which possibly contain false information about the Russian armed forces”, according to a police report quoted in the party's statement.

Yabloko said the “pacifist artworks” were taken away by police “without even being properly packed to ensure their safety”.

One work showed the face of a little girl with big eyes. “Mom, I am afraid of the war,” read the words next to the image, in Russian and Ukrainian.

Since the start of Russia's military campaign in Ukraine, all public criticism has been outlawed including the words “war” and “invasion”.

The authorities have introduced a law with up to 15 years in prison for those who publish information about the Russian army that is deemed false.

Osipova had described the event as a protest and an “anti-war exhibition”.

She has been a fierce critic of the Kremlin for many years, and has been dubbed “the conscience of Saint Petersburg”.

She first staged a protest in 2002, after Chechen gunmen stormed a Moscow theatre and took 850 people hostage.

Since then, she has held regular demonstrations and been arrested several times.