The Asda store in Dewsbury is in 'lockdown' after a man was stabbed in the back outside the store.
Police were called to the store on Mill Street West at 4.47am on Thursday, August 15 to reports of an injured male.
They found a man, aged in his 20s, with a stab wound to his back and slashes to his face.
He was taken to hospital for treatment but his injuries are not believed to be life-threatening.
A man has been arrested on suspicion of causing grievous bodily harm and remains in police custody.
West Yorkshire Police have cordoned off the Asda store and the footbridge nearby and customers are not being allowed into the store.
A spokesperson for West Yorkshire Police said: "Police were called by the ambulance service at 4.47am to a report of an injured male on Mill Street West, Dewsbury.
"Officers attended and a male, aged in his 20s, was found with a stab wound to his back and lacerations to his face. He has been taken to hospital for treatment to non-life threatening injuries.
"A man has been arrested on suspicion of s18 assault and remains in police custody.
"Enquiries are ongoing in the Mill Street West area to establish the circumstances and there will be an increased policing presence in the area."
Anyone with information is asked to contact police on 101, quoting crime reference 13190416321.