A small but colourful demonstration in Washington against the imprisonment of members of the punk band Pussy Riot.

It's been one year since the female rockers' impromptu protest performance in Moscow's main cathedral.

Three band members were sentenced to two years in prison for `hooliganism'. One was later released on appeal.

Jasmine Heiss from human rights group Amnesty International says the ruling was a blow for freedom of expression in Russia.

SOUNDBITE: Jasmine Heiss of Amnesty International, saying:

"These women are incredibly articulate and they are practicing their art, not just free speech, but dissent through art. I think what's so important for us at Amnesty is remembering that the Pussy Riot case is taking place in a larger crackdown on freedom of expression, on dissent in Russia. We're seeing protesters detained by the thousands, people in the streets working against Putin, speaking out against his return to power and some of the new legislation that's coming through, and we're just seeing a tightening on freedom of expression, on the right to dissent, and on basic human rights in Russia,"

The brief obsenity-laced stunt, which urged the Virgin Mary to throw out Russian President Vladimir Putin, enraged the Orthodox Church