Two children have been taken to hospital with burns following a petrol bomb attack on their home in Waterford city tonight.

Two girls, age 11 and one, suffered burns and cuts after a petrol bomb was thrown into their home in Ardmore Park, Ballybeg at around 9pm.

The children were in the sitting room when the attack happened.

The petrol bomb was thrown through the front window and exploded in the room.

The children were on the sofa at the time.

Their grandmother rushed into room and managed to put out the flames with a fire extinguisher.

The children's injuries are said to be serious but not life-threatening.

They are being treated at Waterford University Hospital.

Two other children were upstairs at the time of the attack.

A man in his 20s has been arrested and is being held at Waterford Garda Station.

The scene of the attack has been preserved for a technical examination.