Police are investigating a report of a brick being thrown through the office window of Wakefield MP Mary Creagh.
Ms Creagh said her staff were distressed to discover the damage at the constituency office in Wakefield city centre this morning.
A rear window was smashed at the Labour Party office on Cheapside.
Ms Creagh said: “On Monday morning, a member of my staff discovered that a brick had been put through the window of the office that I share with the regional Labour Party.
“This incident has now been reported to the police, who have reassured me that they are doing everything that they can to track down the individual responsible and bring them to justice.
“My staff and the staff of the Labour Party deserve a safe environment to work in. There is no excuse for this sort of mindless violence in a free and tolerant society.”
Police have appealed for any witnesses to the incident to contact them.
A West Yorkshire Police spokeswoman said: “Police were called to an address on Cheapside in Wakefield at 12.50pm today following reports that a brick had been thrown through a window.
“The building was unoccupied at the time. Enquiries are ongoing to determine the circumstances surrounding the incident.”
“Anyone with information is asked to contact police via 101 quoting 725 of September 12.”