MOSCOW – Police in Moscow and St. Petersburg have detained about 50 people taking part in unauthorized demonstrations against a criminal case filed against 10 young Russians for allegedly taking part in in extremist group that aimed to overthrow the government.

Lawyers for the 10 suspects who were arrested in March say undercover police fabricated the case, writing the group’s radical program and encouraging members to have shooting practice.

Four of those charged are jailed and the others are under house arrest.

The OVD-Info group, which monitors police actions and political repressions, said that at least 40 people were detained in St. Petersburg on Sunday and at least nine in Moscow.

The case has been widely criticized as a glaring example of official abuse of Russia’s law on extremism.