Khodorkovsky & Lebedev Communications Center

U2's first concert in Russia ended in political controversy as Moscow authorities detained Amnesty International volunteers and tore down their booth at the event.

Speaking to the UK's Guardian, Sergei Nikitin, the director of Amnesty Russia, said: "We were collecting signatures to support prisoners of conscience and to call on the [Russian] authorities to investigate the murders of Anna Politkovskaya and Natasha Estemirova. We'd been doing this for about three hours. At 5pm the riot police turned up. They told us we were holding an unlicensed picket, and took away all our placards. We were also strongly recommended to strip off our T-shirts."