OSLO, Norway (AP) — Norway’s intelligence service says it has been warned of an imminent “concrete threat” against the nation from people with links to Islamic fighters in Syria.

Benedicte Bjoernland, the head of Norwegian security service PST, said Thursday the agency had received “reliable information” from a foreign partner about some kind of attack “within days.”

Bjoernland said there was no indication of a specific target.

She said the information involved people who have been fighters in Syria.

According to PST’s assessment last month, about 50 people have traveled to Syria from Norway as foreign fighters, half of whom have returned to Norway. Bjoernland declined to give further details.

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