Police have released CCTV images of a man they want to trace in connection with a serious assault in the city centre.
He was punched by one of the men and fought back before a second man punched him knocking him to the ground.
He received an injury to his neck and the incident is being treated as grievous bodily harm.
The incident happened at about 1.30am on Friday, October 17.
Anyone with any information is asked to contact DC Thimm at Elland Road via 101 or call Crimestoppers anonymously on 0800 555 111.