Loyalists should step back from the brink and call off street protests, unionist MLAs at Stormont have said.
The appeal comes after the attempted murder of a woman police officer in east Belfast.
Speaking in the Assembly, the DUP's Paul Givan described the attack as despicable and said protests should be stopped if they could not be peaceful.
Mr Givan, who chairs the Stormont justice committee, said: "It is vital that those who continue to have protests, if they cannot guarantee that there will be no violence; that there will be no blocking of roads and no disruption to people's way of life, that they do not go out onto the streets and they should desist from that activity."
Loyalists protesting over flags were responsible for 43 illegal road blocks across Belfast on Monday night. Violence flared in four areas.
Police were pelted with bricks, bottles, stones and other missiles. A PSNI water cannon was deployed to quell the disorder.
A PSNI patrol car parked outside the offices of under-threat MP Naomi Long was petrol-bombed while a police officer was inside.
The PSNI has blamed loyalist paramilitaries from the UDA and UVF for orchestrating the violence.
Ulster Unionist and former police officer Ross Hussey, who sits on the Northern Ireland Policing Board, said: "Who would bring a petrol bomb to a peaceful protest?
"The people that did this went with murderous intent. These people are not loyalists. They are nothing other than terrorists... and I condemn them for that."