Swedish authorities say they have called off their weeklong search for a suspected submarine in the Stockholm archipelago. Military authorities have ordered naval and amphibious forces to end their hunt for the submarine, though some ground forces will remain involved. Last Friday, Sweden's military launched its biggest anti-submarine operation since the twilight of the Soviet Union after receiving credible reports of foreign underwater activity. Military officials haven't blamed any country for the suspected intrusion, though most Swedish defense analysts say Russia would be a likely culprit. Earlier this week, the military said it was willing to use armed force to bring the sub to the surface, but admitted finding it would be very difficult. (More Sweden stories.)