Tracy and Chris Redshaw were dropping off their daughters Candra and Lilly at nursery when the dog attacked them
The father of three-year-old twin girls has described how they were attacked by a dog outside their school.
The dog, thought to be a Staffordshire-type terrier, escaped from a property near Red Hall Primary School in Darlington at about 08:55 BST.
Chris Redshaw described the "surreal" moment he saw one of the girls being "dragged along the floor" by the dog.
A 44-year-old local woman has been arrested on suspicion of allowing a dog to be dangerously out of control.
Police said one girl suffered a head injury and the other bite wounds to her lower back. Both required hospital treatment.
Mr Redshaw received bite wounds to his hands as he tried to fend off the animal.
Chris Redshaw said his daughters were left with a head and back injury, but were OK
Durham Police said the dog was captured and will be destroyed.
Mr Redshaw, who was dropping his daughters off at the school's nursery, said: "I heard my wife screaming and shouting and as I turned around it was a surreal moment because all I could see was my daughter Candra being dragged along the floor by the dog.
"It was shaking her from side to side. I managed to jump onto the dog and had to put my own hand into its mouth to get it to release her.
"Then it went for my other daughter Lilly and got her on her bum. I grabbed hold of the dog and got it off her and by then the owners were there to retrieve it.
"We waited in the school for the police and ambulance to come. It's been very traumatic for us all."
The dog escaped from a property close to Red Hall Primary School
A Durham Police spokesman said: "Obviously this was a truly terrifying incident for those involved.
"It is the last thing you expect to happen at the school gates and was very distressing for anyone in the area at the time.
"We would like to reassure residents that this was an isolated incident."
He added officers would be in the area to offer support and reassurance to people living nearby.
"We hope those involved get the care and attention they need and make a speedy recovery while our investigation into what happens continues," he said.
No-one from the school was available for comment.
