Paul McCartney meets fans and signs copies of his album 'New' at HMV, Oxford Street on October 18, 2013 in London, England.
Photo by Ian Gavan/Getty Images

Paul McCartney is once again trying to help Russian political prisoners.

Earlier this year McCartney wrote a letter to Russian officials in support of parole for Pussy Riot, the female band that was jailed in August 2012 for a "breach of public order motivated by religious hatred." He didn't have much luck, as they are still behind bars, but that hasn't deterred him from once again reaching out to Russian president Vladimir Putin. This time he's urging Putin to intervene to help 30 people jailed after a Greenpeace protest in the Arctic.

Macca writes, "It would be great if this misunderstanding could be resolved and the protesters can be home with their families in time for Christmas. We live in hope." Putin has yet to respond, but the Russian ambassador to Britain has, saying the situation of the detainees "is not properly represented in the world media." You can read McCartney's entire letter at