Tension prevailed here on Thursday after several establishments, including a mosque and a madarsa, which were illegally constructed on government land, were demolished.
The situation, however, turned violent after the mosque and the madarsa were razed in the Vanbhulpura area, as enraged locals pelted stones on the police personnel and mediapersons.
Several police personnel sustained injuries in the attack, sources said. The mob also damaged a JCB machine and set a number of vehicles on fire.
Shoot-at-sight order has been issued while a curfew has also been imposed in the violence-hit area.
Taking note of the violence, Chief Minister Pushkar Singh Dhami convened a high-level meeting as he appealed to the people to maintain peace.
Haldwani Mayor Pankaj Upadhyay said the madarsa and mosque were illegally constructed.
Heavy deployment of police personnel has been made in the city.