A $500m (£385m) warship is in danger of sinking to the bottom of a Norwegian fjord after colliding with an oil tanker off the coast of the Scandinavian country.

The KNM Helge Ingstad, a 5,290 ton frigate armed to the teeth with missiles, torpedoes and depth-charges was on an exercise in Hjeltefjord near Bergen when it ran into the other vessel.

As many as eight people are thought to have been injured when the ship, which is equipped with its its own submarine-spotting helicopter, ploughed into the Maltese flagged commercial vessel.

Sources told the AFP news agency that a “small oil slick” emanating from the Norwegian warship had been detected and that it had taken on “on a lot of water and there is a real danger that it sinks where it is”.

Nato's Allied Maritime Command said in a statement: “Due to the damage to the frigate it was moved to a safe place.”

The oil tanker, the Sola TS, has returned to port for an inspection and is not thought to have spilled any of its polluting cargo during the incident. It is understood to have been UK-bound at the time of the accident.

Oil production was temporarily halted in the area as a precaution, news agencies report.

The collision happened in the small hours of the morning during a training exercise.