A dog was also killed in the knife attack
A British backpacker has been stabbed to death at a hostel in Australia by a man who allegedly shouted "Allahu Akbar" as he attacked her.
The backpacker has been named in British and Australia media as 21-year-old Mia Ayliffe-Chung from Derbyshire in England.
Police said they found a "terrible scene" when they arrived at the scene of the knife attack in Home Hill, north Queensland.
Two men were injured, including a 30-year-old Briton who was taken to Townsville Base Hospital, where he is reportedly in a critical condition.
A dog was also killed in the attack, which happened at around 11.15pm local time on Tuesday and was witnessed by up to 30 people.
Police have arrested a 29-year-old Frenchman and recovered a knife, which they believe was used in the attack.
Investigators said they were probing possible extremist links, while mental health issues and drug use were also lines of inquiry.
Queensland Police Service Deputy Commissioner Steve Gollschewski said: "We are not ruling out any motivations at this stage. We wish to reassure the community - we are not looking for anyone else."
He said the suspect had been in Australia for about a year on a temporary visa.
He said: "This person appears to have acted alone. He is a visitor to Australia and has no known local connections, however investigations are ongoing."
The British High Commission in Australia said it was providing support to the families of the victims.