The Chief Minister, who along with his father JMM supremo Sibu Soren, was in the city to take part in rituals after the death of former deputy Chief Minister Sudhir Mahto.
Peeved over the state government for not accepting the memorandum in support of their demands on various issues, AJSU activists were holding a rally to show Soren the black flag but were rounded up well before they could have reached the venue, police said, adding they were later released.