A senior official in Germany said Wednesday that organized criminal groups were likely behind a museum heist that stole millions in ancient Celtic gold coins.

Bavarian minister of science and arts Markus Blume told public broadcaster BR that the Celtic and Roman Museum in Manching was "highly secured" and that there is an increased possibility that the thieves were part of an organized criminal organization.

Blume stated that the museum's security systems, along with the town's entire telephone network, were disabled during the heist. He commented the thieves had "incredible criminal energy."

"It's clear that you don't simply march into a museum and take this treasure with you," Blume said.

The Celtic-Roman Museum in the evening
The Celtic-Roman Museum in Manching Armin Weigel/DPA

The ancient Celtic coins were stolen Tuesday and are estimated to be worth several million euros, according to the German news agency DPA.

The 483 coins were discovered in 1999 during excavations of an ancient settlement near the town of Manching, about 40 miles north of Munich, where the coins were displayed at the local Celtic and Roman Museum.

DPA also reported three other items were stolen from a second display cabinet, dating back to around 100 B.C. Officials estimate the value of the coins, which weighed a total of about 8.8 pounds, at millions of dollars.

The area was once the site of a large Celtic settlement, the Oppidum of Manching. Archaeologists continue to excavate in the area, and the Bavarian Office for Historical Preservation considers it one of the most important archaeological sites north of the Alps.

Police and prosecutors planned to hold a news conference in Manching on Wednesday afternoon.