At least four people have died in violence in a northern Indian state after authorities demolished a mosque, alleging it was constructed illegally.

Violence broke out in Uttarakhand's Haldwani town during what police แทงบอลufabet say was an "anti-encroachment drive".

Authorities said the drive was launched to clear illegal constructions, including the mosque and an adjoining madrassa (religious school).

But Muslims who prayed at the mosque say they have been unfairly targeted.

Hundreds of protesters and police personnel were injured in the clashes which broke out on Thursday evening.

Videos showed protesters setting fire to vehicles and pelting stones and the police firing tear gas at them.

A curfew has been imposed and the state has issued "shoot at sight" orders to bring the situation under control.

Officials said the latest action was based on a high court order asking authorities to clear illegal settlements from the area.

District Magistrate Vandana Singh said the mosque and the madrassa were demolished because they were illegally built on government land and were not registered as religious structures.

"The drive was not targeted towards any particular community. It began peacefully but a mob attacked officials soon after, leading to violence," Ms Singh said, adding that authorities had given the mosque's administration prior notice about its demolition.

Locals have denied this and said the mosque was demolished before the court could give a final decision in the case.