Police said Udaltsov was taking part in a demonstration in support of the Astrakhan branch of the Just Russia party, Interfax reported. Mayoral candidate and former Just Russia parliamentarian Oleg Shein has been on a hunger strike for 26 days in protest of alleged vote rigging in last month's Astrakhan mayoral election.
Udaltsov told Interfax that around 30 people participated in Tuesday's rally.
At an event Monday outside Astrakhan's office near the Sukharevskaya metro station, Udaltsov vowed to return to the building Tuesday. "I will be here Tuesday at 2 p.m.," he said, standing outside the office with a large white poster reading, "People are dying in Astrakhan! Putin and Zhilkin: You are responsible!" Alexander Zhilkin is the governor of the Astrakhan region.