MADISON, Wis. -- Madison police are urging people to lock up their mopeds following a spike in moped thefts downtown over the last month.

Police said they have handled between 20 and 30 reports of stolen mopeds in the last month.

Once stolen, police said that mopeds can be difficult to recover.

"All these cases come in, and we don't have the resources to investigate every single stolen moped that occurs in the downtown area," said Mike Hanson, public information officer with the Madison Police Department.

Police encourage moped owners to use a U-lock on the tire or lock the moped to a fixed object, WISC-TV reported.