Moscow police have detained about 10 activists who took part in a demonstration in support of jailed oil tycoon Mikhail Khodorkovsky on his 48th birthday.
Around 50 young activists wearing red T-shirts with Khodorkovsky's portrait on them marched down the Arbat pedestrian street handing out shirts and balloons.
Suddenly from the rooftop of a building along their route, a large plastic banner was unfurled wishing Khodorkovsky a happy birthday and freedom.
The detained activists were driven away in police vehicles.
Demonstrations also were held in St. Petersburg and London.