MOSCOW, September 10 - RAPSI. A lawyer for the now infamous punk band Pussy Riot has been summoned for questioning over his role in a May 6 opposition rally that broke out in a civil unrest riot.

Investigators say Mark Feygin called for protesters to disobey police instructions at the protest, which came on the eve of Vladimir Putin's inauguration for a third presidential term.

Mass opposition rallies began in Moscow on May 6. Clashes with the police flared up during a march across Moscow, which had been approved by the authorities. Tens of people on both sides were injured. The police detained over 400 protesters. The court has so far placed 13 people in custody for taking part in the rallies. Several have been charged with calls for mass unrest.

Feygin said the order to report to investigators on Monday, which could see him taken into custody, were timed to prevent him from taking part in an appeal hearing on October 1 against the two-year sentence handed out to three members of Pussy Riot at a controversial trial last month.

On February 21, 2012, five young women wearing brightly colored balaclavas stood at the altar of Moscow's Christ the Savior Cathedral to perform a protest song entitled, "Holy Sh*t." Shortly thereafter, an edited video of the performance that was uploaded to the Internet incited a public outcry.

Pussy Riot members Nadezhda Tolokonnikova, Maria Alyokhina and Yekaterina Samutsevich were convicted of disorderly conduct and sentenced on August 17.

Feygin also said the move could stop him from attending an anti-Putin rally set to take place in Moscow this weekend.