Supporters of the Russian punk band Pussy Riot have staged a flash mob protest on the steps of Moscow's main cathedral.

Three members of the group are currently on trial charged with hooliganism, after performing a 'punk prayer' against Vladimir Putin on the altar of Russia's Christ the Saviour cathedral in February.

Guards moved in quickly to disperse the crowd who gathered on Wednesday, wearing colorful balaclavas and holding black cards spelling out the phrase, 'blessed are the merciful'.

A Moscow court is expected to issue a verdict in the Pussy Riot case on Friday.

Prosecutors want each of the three women on trial sentenced to three years in prison.