UN Secretary-General Antonio Guterres is "very saddened" by the death toll and injuries sustained during the protests in Delhi against the Citizenship (Amendment) Act (CAA), his spokesperson Stephane Dujarric said on Wednesday.

"He is very saddened by the reports of casualties following the protests in Delhi and as he has done in similar circumstances, he calls for maximum restraint and for violence to be avoided," Dujarric said in response to a reporter's question at his daily briefing.

As many as 28 people have died in clashes this week and about 200 have been injured.

Several businesses, residences and at least one mosque have been damaged in the riots.