Small-statured thieves are stealing from passengers' luggage by hiding in the baggage compartment on a Swedish bus line, according to media reports.

Travelers on the Swebus line have been advised to keep valuables on their person after reports of robberies by "mini thieves," who may hide inside large sports bags in the luggage compartment where they emerge to steal from baggage while the bus is en route, UPI and TheLocal.se have reported.

Click here for TheLocal.se report.

Click here for UPI's report.

"It is very possible that a small person is being placed in a bag in order to search through the other bags," Swebus spokeswoman Pia Kråvall said. "We have recently received several reports of thefts, including on the Västerås to Stockholm line."

One traveler reportedly told police she saw two men speaking poor English squeezing a very large bag into a cramped luggage compartment despite there being an empty compartment in the back of the bus, TheLocal.se reported.

Swebus is reportedly looking at ways to tighten security.