A man and a woman were assaulted in Motherwell in the early hours of Monday.
Around 0015 hours a man aged 53 and a 47-year-old woman left The War Office pub in Milton Street.
The man became involved in a row about a taxi with another man who punched him, causing him to fall and injure his leg. The man then punched the woman before leaving in the taxi.
Both victims were taken to hospital and released after treatment. The suspect is described as 5ft 8 to 6ft, slim and wearing a black baseball cap and grey clothing.
Detective Constable Gerry Hattie appealed for witnesses, particularly three women in a car, to come forward.