A man has been arrested after three children were injured when a house was petrol bombed in Waterford.

It happened in Ardmore Park around 9 o'clock last night.

An 11-year-old girl and her one year old sister, who had been in the living room, are being treated for burns in hospital, although their injuries are not believed to be life-threatening.

A boy was also injured.

It's understood the girls' grandmother put out the flames with a fire extinguisher.