American activities in Scandinavia have come under the spotlight after revelations US embassies conducted surveillance inside the countries without the governments’ knowledge.
Sweden is the latest state, along with Denmark and Norway, to confirm the potentially illegal spying operations.
Earlier, Sweden’s Justice Minister Beatrice Ask said an investigation had been launched into the affair.
On Friday, it was revealed that the American embassy in Oslo had surveyed some Norwegian residents for security purposes for more than ten years.
Norway has demanded an explanation from Washington.