Authorities closed schools and suspended internet services in a northern Indian city on Monday, officials said, a day after four people were killed in clashes sparked by an official survey probing whether a 16th-century mosque was built on a Hindu temple.

The death toll from violent protests in India sparked by a survey into whether a centuries-old mosque was built on a Hindu temple has risen to six, an official said on Tuesday. Around 20 police officers were also wounded during the violence on Sunday in Sambhal in India’s northern state of Uttar Pradesh, district magistrate Chirag Goyal told AFP.

The clashes between locals and police over the Mughal-era Shahi Jama Masjid in Sambhal, which is at the centre of a legal dispute claiming that it was built on a Hindu temple site, led to the death of four Muslim youths and resulted in injuries to at least 20 police officers on Sunday.

A first information report was filed against Samajwadi Party MP Zia-ur-Rahman Barq and the son of a party MLA in connection with Sunday’s clashes.