Officers cordoned off part of a Sheffield street after a man suffered serious facial injuries.
Police were alerted at 8.45pm by the Yorkshire Ambulance Service a 'young man' had receives injuries on Stanley Street with the junction with the Wicker.
Pools of blood were present on the pavement and inside the shop door way of Wicker News & Groceries.
Unconfirmed reports suggest the male victim was attacked with a glass bottle and was later taken to Northern General Hospital for treatment.
Crime Scene Investigators attended the scene to carry out enquiries.
A South Yorkshire Police spokesman said officers were still trying to find out how the man came to receive his injuries.
"We believe a young man had gone into one of the shops close by with serious facial injuries. We are trying to establish the who, what, where and when why concerning this particular incident at this time."
More updates to follow.