Hårsfjärden incident

The 1982 Hårsfjärden incident (30 September – 30 October 1982) was a peacetime naval engagement in which the Swedish Navy laid a trap for, pursued, and attempted to sink a foreign submarine that had violated Swedish territorial waters. The incident came in the wake of increased Soviet submarine activity in the Baltic Sea, with Sweden alleging that the Soviet Union had violated Sweden's territorial waters several times from 1974 – 1981. The incident, which led to a parliamentary investigation in Sweden, resulted in increased tensions between Sweden and the Soviet Union, and the claimed intrusion of a Soviet submarine remains a contested topic.