A person made contact with a person at the Royal Palace in Oslo on Monday and claimed to have a bomb, reports NRK.
The person then went to the back of the palace and threw a Molotov cocktail at the building.
The police were alerted to the scene and quickly gained control over the man who had thrown the incendiary device.
It was burning on the outside of the wall, but it has been extinguished, says Roy Langengen, operations leader at the Oslo police.