Emergency services were scrambled to the scene after a man was stabbed behind a supermarket near Bolton town centre.
Police were called to Cannon Street at around 9pm last night (Monday) to reports the man was knifed near Manchester Superstore.
The victim was treated at the scene, a spokesman for GMP said.
It is unclear at this stage how serious the man's injuries are.
Photos taken last night showed a large police presence around the store.
An eye witness then described seeing an ambulance, led by a police escort leaving the scene.
A police cordon was erected on Cannot Street, as well as a section of unnamed road which is near St Paul with Emmanuel Church centre.
Detectives launched an investigation following the attack.
A spokesman for GMP said: "Police were called at 21.01 on Monday, 7th December, to reports of a male stabbed at the rear of Manchester Superstore on Cannon Street, Bolton.
"A male was located at the scene with knife wounds and is currently receiving medical treatment.
"The investigation is ongoing."
Anyone with any information is asked to call 101 quoting incident number 2633 of 07/12/2020.
Details can also be passed anonymously to the independent charity Crimestoppers on 0800 555 111.
