A crocodile attacked a man swimming in a waterhole in a remote part of Australia\'s Northern Territory before dragging a seven-year-old girl under, witnesses have told police searching for the child. An extensive search was underway Saturday for the girl who was last seen swimming at the natural pool at an outstation about 340 kilometres (210 miles) east of the city of Darwin the previous afternoon. The girl was swimming with other children and an adult at the time. \"Witnesses have told police that a crocodile attacked the male adult before pulling the girl under water,\" Senior Sergeant Shaun Gill said. \"The crocodile is estimated to be about 2-3 metres (6.6-10 feet) in length and the billabong (waterhole) is described as being approximately 200 metres long by 20 metres wide.\" Police are coordinating the search which includes a ranger experienced in crocodile management and volunteers. \"An extensive land and water search commenced at first light this morning and will continue throughout the day,\" Gill said in a statement. A search by police and volunteers on Friday failed to find the child and extra police were flown to the remote area about 100 kilometres from the Aboriginal community of Maningrida. Saltwater crocodiles, which can grow up to seven metres (23 feet) long and weigh more than a tonne, are a common feature of Australia\'s tropical north. They have been protected since the 1970s and their numbers have increased steadily since, along with the number of human encounters.