According to a police officer, a mob of stone pelting protesters clashed with the police in uptown Maisuma locality and in areas around city centre Lal Chowk.
"Police had to intervene to bring the situation under control," he said.
A youth, identified as Faizan, 14, sustained critical injuries when police used batons and tear smoke shells to quell the mob.
"Six policemen and three other protesters have also been injured," the officer was quoted by news agecy as saying.
The protests erupted in the locality following a shutdown call by Geelani, who claimed the protest "is part of a peaceful resistance programme for vacation of lands occupied by the army in Kashmir."
Shops and businesses remained closed here and public transport went off the roads.