Paul McCartney tells Russian punk band to "stay strong"

(CBS/AP) Paul McCartney is the latest star to throw his support behind a Russian punk band whose members face prison for a stunt against President Vladimir Putin.

In a letter released Thursday, the former Beatle urged three members of Pussy Riot to "stay strong" and called on authorities to allow them freedom of speech.

McCartney noted that "I and many others like me who believe in free speech will do everything in our power to support you and the idea of artistic freedom."

He added, "Many people in the civilixed world are allowed to voice their opinions and as long as they do not hurt anyone in doing so. I believe this is the best way forward for all societies."

The band members have been in jail for more than five months because of an anti-Putin prank in Moscow's main cathedral, and face a maximum seven years in jail. They were arrested on charges of hooliganism motivated by religious hatred.

Celebrities including Madonna, Bjork  and  Peaches have called for them to be freed.

A judge is due to rule on the band's case Friday.