Finnair pilots have reported GPS jamming in the area around Kaliningrad, according to the Reuters wire service.
Finnair flies over Russia's Baltic exclave on many of its European and Asian routes. GPS jamming has also been seen near Finland's eastern border, with ten pilots reporting similar instances this week.
The Lithuanian airline Transaviabaltika's flights have been prevented from landing at Savonlinna because the regional airport has no alternative navigation equipment.
Flights into Savonlinna suspended
"Our plane was flying from Tallinn to Savonlinna on Sunday evening," said the airline's representative Jyri Koponen. "It got to round about Kouvola when all of a sudden the GPS signal disappeared. At first, I suspected that there was some kind of fault with the equipment. The plane turned around when the fault was found, in line with normal procedures. When it arrived back in the Helsinki area, all signals were working fine again."
The airline tried to fly the route again with another plane, which suffered the same fault. They have not made any further attempts at reaching Savonlinna.
Flights between Savonlinna and Helsinki are also suspended at least until early next week, according to municipal authorities.
In 2018, Finland demanded information from Russia about aviation GPS jamming in Finnish Lapland during Nato military drills in northern Finland and Norway. Moscow later said Finland had presented no evidence.