A museum in Norway has appealed for help from its counterparts in Ireland after 400 Viking artifacts were stolen from its premises.

The collection, some of which was originally taken from Ireland by marauding Vikings more than a millennium ago, was stolen from the University Museum of Bergen on the country’s southwestern coast on August 12.

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The Irish items have been on display in the National Museum of Ireland in the past and, in a karmic twist, local police are now said to be investigating a possible connection to Irish criminal gangs.

“It is difficult to find the right words to describe my feelings towards what has happened,” museum director Henrik von Achen said in a statement.

“One of our primary tasks is to protect cultural heirlooms. When we fail to do this, no explanation is good enough. This hits us at a very soft spot. We are all very shaky and feeling a sense of despair,” he added.

The perpetrators gained access to the museum through a seventh floor window which they reached by climbing an outside scaffold.

Speaking to Norwegian news site Dagbladet, the university’s senior vice president, Kjell Bernstrom, put the surge in interest in Viking-age artifacts down to the popularity of HBO show ‘Game of Thrones’ and said that the theft was a wake-up call to those concerned about the security of historical items.

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“It is obvious that our security work has not been good enough. We have already taken a series of tight measures, and are now planning more and more comprehensive measures,” he said.

"We are prepared to spend the money it will cost."

Bergen police detective Even Aspli revealed that there were no concrete suspects yet, but police believe it is “possible” the artifacts may have been taken out of the country.

“Experts on this material say it would be very hard to sell, as it would be widely recognized,” he said.

Pictures of the “irreplaceable pieces of history” registered as stolen are available on the museum’s Facebook page.