Russian police on Saturday detained around a dozen anti-Kremlin opposition activists after they turned up near Red Square for a rally to support their jailed colleagues. Police detained 13 out of around 30 activists who had planned to stage a rally in central Moscow, said Yekaterina Mochalova, one of the detained activists. \"We simply gathered near a monument when the police detained us,\" she told AFP from a police vehicle. Some activists held placards with portraits of jailed activists, while one black-clad woman had a funeral wreath, a ribbon attached to it reading \"Russian democracy,\" an AFP photographer reported from the scene. Mochalova said that police chose not to detain a man who stood nearby with a placard reading \"For Putin\". The activists, part of the leftist group the Left Front, had planned to hold a picket on Red Square, but police had cordoned it off. The rally was planned in support of activists prosecuted for their participation in a May 6, 2012 rally, which turned violent one day before Vladimir Putin\'s inauguration. Left Front leader Sergei Udaltsov is under house arrest until April 6. Critics complain of a tough crackdown on dissenters after Putin returned to the Kremlin for a third term despite huge protests against his 13-year rule.