Iranian authorities describe the protests as riots.
Officials “must apply the law of an eye for eye” against those who “have harmed people’s lives and property with bladed weapons and firearms”, the lawmakers said.
“We call on all officials in the country, including the judiciary, to deal as soon as possible with the enemies of God,” they said in the declaration, published by parliament’s press agency.
The lawmakers also urged the judiciary to “deal decisively with the perpetrators of these crimes and deal with all those who incited the rioters, including certain politicians”, they added.
Earlier Sunday, state media and the Revolutionary Guards said four Iranian police officers and one “terrorist” had been killed in separate incidents.
Amid the wider unrest, clashes have also rocked Sistan-Baluchistan province, which borders Pakistan and Afghanistan, sparked by the alleged rape of a local teenage girl by a police chief.