Until he was finally killed in a never resolved 1986 assassination
After a Soviet submarine ran aground in Swedish territorial waters in 1981 the country was haunted by several hundred more sightings of submarines, all of which were blamed on the Soviets, and caused much panic in public opinion, greatly embarrassing the non-aligned Social Democrat government led by Olof Palme and its efforts to create detente in Europe.
Sightings continued for half a decade until the never resolved assassination of Olof Palme in 1986 and the end of the Cold War in the late 1980s.
10 years later, high ranking US and British officials causally revealed in interviews that NATO had sent submarines into Swedish waters — with the Swedish Navy High Command being informed of the matter, but with neither the Swedish militar brass nor US/UK/NATO informing the elected Swedish government.
Submarine-sightings returned in 2014, during the New Cold War.