A man is being held in police custody after a man, a police officer and a police dog received stab wounds.
The officer and the dog were injured when they tried to arrest a 21-year-old man suspected of stabbing another man in the stomach, police said.
Police were called to Oulton Road in Ipswich, Suffolk, where they found a man with a wound to his stomach.
A Suffolk Police spokewoman said that officers tracked a suspect down and stopped him in a nearby road but when they tried to detain him using a Taser, the policeman was stabbed in the arm and the animal received a stab wound to its leg.
The force spokeswoman said: "Following information gathered, police tracked a man believed to be the offender and stopped him in Nacton Road.
"He was agitated, in possession of a knife and officers attempted to detain him by using a Taser.
"A police dog and handler were at the scene and in the attempts to arrest him, both the animal and the police officer were stabbed."
The 21-year-old was arrested and taken into custody, she said.
The man with the stomach wound was taken to Ipswich Hospital and was said to be in a stable condition. The police officer was also taken to Ipswich Hospital.
The spokeswoman said the dog was at a veterinary clinic undergoing an operation.