U2's first performance in Russia was overshadowed by several arrests before the band took the stage.
Police took members of the rights group Amnesty International into custody after they tried to hand flyers to concert-goers outside the venue.
A spokesperson for the group's Moscow office said U2's management had granted them permission to distribute leaflets.
"I don't know if Bono knows about what happened to us," Sergei Nikitin told BBC News.
"It was a typical publicity event, which this organisation has carried out in every city where U2 has performed."
Volunteers from U2's AIDS fund, One, were also apparently forced out of Moscow's Luzhniki stadium by police last night (August 25).
The gig went ahead, despite the arrests, and saw singer Bono invite anti-Kremlin activist Yuri Shevchuk on stage to perform 'Knockin' On Heaven's Door'.
Earlier in the week, the singer met with Russian President Dmirty Medvedev to discuss his well-publicised campaign efforts.

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