MOSCOW: Security guards scuffled with masked protesters who demonstrated outside Moscow's main cathedral on Wednesday in support of three members of the Pussy Riot punk band who are on trial for staging an irreverent protest at the same church.

Witnesses said 18 demonstrators in colourful balaclavas like those worn by the band members mounted the steps of Moscow's Christ the Saviour Cathedral and held up black cards with white letters spelling out the phrase "Blessed are the merciful".

Guards moved swiftly to disperse the demonstrators and treated some of them roughly, Internet TV channel Dozhd reported. Pussy Riot supporters said on social media that at least two people had been detained.

A Moscow court is to issue a verdict on Friday following the trial of the three women who sang a "punk prayer" on the altar of Christ the Saviour in February, calling on the Virgin Mary to rid Russia of Vladimir Putin, then prime minister.

Prosecutors want the judge to convict Nadezhda Tolokonnikova, 22, Maria Alyokhina, 24, and Yekaterina Samutsevich, 30, of hooliganism motivated by religious hatred and sentence each to three years in prison.

The three women say they were protesting against close ties between the state and the Russian Orthodox Church, whose leader supported Putin during his successful campaign in a presidential election in March.

The defendants have been held in jail since shortly after their performance, which offended many people in mostly Orthodox Christian Russia. Kremlin critics see their trial as part of a crackdown on dissent as Putin starts a new six-year term.