Some 400 objects of Viking origin were stolen from a museum in Norway sometime between Aug. 11 and 13. The pieces were due to be transferred to a more secure location on Aug. 14.

"If the stolen objects are not returned, this is by far the most terrible event in the 200 years of Norwegian museum history," the director of the University Museum of Bergen in southwestern Norway, Henrik von Achen, told AFP.

The items were small metal objects and jewelry. The museum director described the pieces as not having significant monetary valuable as metal, but their loss culturally is "immeasurable."

Police say the thieves climbed scaffolding on the museum's exterior to reach the 7th floor where the objects were temporarily stored. An investigation continues.