Lawyers for a Russian artist and musician who replaced supermarket price tags with demands for an end to Moscow's war in Ukraine will on Monday urge a judge to free her after a state prosecutor sought an eight-year jail term.

Alexandra Skochilenko, 33, known to her friends as Sasha, has spent over 1½ years in prison in St. Petersburg as the Russian legal system deals with her case. Critics say it is part of a crackdown on anyone who speaks out against Moscow's "special military operation".

Authorities have detained nearly 20,000 people for anti-war activity and opened over 800 criminal cases against anti-war dissidents, according to the OVD-Info rights group. The justice ministry has designated the rights group a "foreign agent" and its website is blocked in Russia.