Two men are in a serious but stable condition in hospital after they were stabbed at a club in Birmingham city centre.
The incident happened at the Medusa club near Suffolk Street Queensway in the early hours of Saturday.
One of the men suffered a stab wound to the chest and the other had a wound to the stomach, West Midlands Police said.
The club was cordoned off for a forensic search after the force was alerted at about 0245 BST.
Police said inquiries were at an early stage and the circumstances surrounding the incident were unclear.
The force wants to speak to anyone who was at the club on Friday night and into the early hours of Saturday morning.
Anyone with information has been asked to talk to officers at Birmingham Central police station.