The Garda Public Order Unit was sent to back up firefighters in the Cherry Orchard area of west Dublin last night.
Dublin Fire Brigade was dealing with two cars set on fire at Orchard Lawns in Cherry Orchard.
A number of youths who had gathered nearby were dispersed and the scene has been preserved for a forensic examination.
Gardaí say no injuries have been reported and no arrests were made.
Local Sinn Féin councillor Daithí Doolan says people are on edge already.
Mr Doolan called for "calm and control in these difficult times".
"We are all in uncharted waters, I think people are a bit on edge at the moment," he said.
"I would urge young people to take a step back, look after each other, show support and solidarity for our neighbours, particularly older people and those feeling fragile and infirm at this moment.
"Let's think of them, let's pull together."