Norwegian police have found a suspicious package under a car parked at the US embassy building in Oslo.

They have cordoned off a large part of the downtown area of the city as a precaution.

Dozens of police officers have evacuated the underground rail station near the embassy and sealed off a large perimeter near the embassy.

It is located adjacent to the royal palace.

Police declined further comment.

It is believed the area around the Embassy and the adjacent Royal Palace are being evacuated after the device was discovered under a parked car.

The neighbourhood is also home to residential and office buildings.

Reports say police have also blocked off streets around the embassy.