“It was a harmless powder. We don’t know exactly what it was yet, but the tests showed it was harmless,” a police duty officer told AFP.
The embassy building, located in the centre of the Swedish capital, was evacuated after embassy staff discovered the letter on Tuesday afternoon. Rescue teams put embassy employees through decontamination procedures as a precautionary measure.
Swedish media reports said the letter was sent from Denmark but the identity of the sender was not known.
The Danish embassy in Stockholm has been attacked several times in recent years. In January, an embassy vehicle parked outside the mission was set on fire in an attack claimed by a group calling itself Global Intifada.
The same group claimed responsibility for vandalizing the embassy in September 2004 by breaking windows and spray-painting the hall of the building red.
That attack was a response to Denmark’s support for the US-led war on Iraq, the group said.
Following the September 2001 attacks in the United States, a wave of anthrax alerts were recorded around the world, after letters filled with a suspicious white powder were mailed to various recipients.
Most turned out to be hoaxes, though five people died and 17 were infected in the United States after handling anthrax-laced letters.
Anthrax is a bacteria which can be deadly if inhaled. Symptoms include fever, sweat, and chills, but typically they do not manifest themselves for several days.