A six-year-old girl has needed surgery after a dog savaged her face near a playground in south-west London.
The girl was mauled by a Staffordshire bull terrier-type dog at Heathfield Recreation Ground, Powder Mill Lane, Twickenham, on Thursday afternoon.
She lost several teeth and suffered a one-inch (2.5cm) cut to the lip.
The owner, a man in his 30s with black hair, took the dog away after the attack and left the scene, police said.
Det Ch Insp Martin Ward of the Metropolitan Police said it was "an unprovoked attack on a very young child".
"We are making extensive inquiries to trace the owner and are appealing for witnesses, or anyone who may know who the owner of this dangerous animal is, to please come forward."