Sweden's already strained relations with the Soviet Union are taking a turn for the worse. Moscow has announced it could not confirm that a Soviet military aircraft flew into Swedish airspace and over Swedish territory for five minutes in early August.
The Soviet response late Tuesday amounted to a denial of the widely publicized incident and stirred consternation among the Swedish press and public. Prime Minister Olaf Palme will chair a Cabinet meeting Friday where the Soviet reply will be a major subject of discussion.
He will probably announce Sweden's next diplomatic move then, government sources say.
Sweden is expected to take a tough stance, making public the films or videotapes of radar images of the Aug. 9 incident in which a Soviet SU-15 fighter flew into Swedish airspace and over Gotland Island while apparently tracking a Swedish civilian airliner.
The SU-15 is the type of fighter that shot down Korean Air Lines Flight 7 as it flew through Soviet airspace a year ago.
Bo Huldt, acting director of the Swedish Institute of International Affairs, said the Soviet response to Sweden's protest could be a reflection of the generally chilly relations between Moscow and the outside world.
The Soviet attitude, he remarked, would not improve what he called ''a frozen climate'' between Sweden and the Soviet Union that started with the 1981 grounding of a Soviet submarine near a Swedish naval base.
''From everything we know, these (flight) operations are controlled from the ground and the amount of independent maneuvering is small,'' Huldt said. ''We could have expected some admission of technical error, but a flat denial fits in with the general image of how the Russians are behaving internationally.''
Foreign observers said the Soviet response would serve to drag out publicity about the incident.
An official at a well-known military think tank said the Soviets were trying to bully Sweden in a pattern consistent with Moscow's denials of Sweden's claim that Soviet submarines operated in Swedish waters in the fall of 1982.
The Soviet response to the Swedish protest appeared almost deliberately timed to catch the Swedish government off guard. Prime Minister Palme, Defense Minister Anders Thunborg, and Foreign Minister Lennart Bodstrom were all traveling abroad when the Soviet verbal response was delivered to a middle-level official at the Swedish Foreign Ministry.