Police were called out to deal with an armed robbery on Thursday morning when a gang stopped and tried to steal the high-value cargo in a G4S van on the main road between Helsinki and Turku.
The G4S van was staffed only by a driver, with no other employees present. The gang failed to steal anything and fled the scene quickly, and police are now looking for 5-6 individuals.
"The robbers left the scene in two vehicles, but they probably initially had a third vehicle which was found burnt-out on the hard shoulder," said Timo Malinen of south-west Finland police.
The culprits fled in a blue Mercedes and a silver Ford Transit, both of which were found abandoned near the scene of the crime. The suspects are believed to have continued in other vehicles.
"There were 5-6 of them in all," said Malinen. "The emergency services were notified of automatic weapons, and they were also discharged. There were definitely Finns among the group, at least, as they spoke Finnish at the scene."
Police initially closed the road in both directions, before opening the Turku-bound side of the highway. Motorists heading to Helsinki along the route can expect diversions.