STOCKHOLM, Sept 4, 2025 (BSS/AFP) - GPS interference affecting aviation over the Baltic Sea region has risen sharply since 2023 and now occurs almost daily, Sweden's Transport Agency said on Thursday, pointing the finger at Russia.

The number of interference incidents with global navigation satellite systems (GNSS), such as GPS, in Swedish airspace has risen from 55 in 2023 to 733 this year as of August 18, according to new data presented by the Transport Agency.

"We have done analyses over a longer period and collected data. We can conclude that the interference is originating from Russian territory," Andreas Holmgren, in charge of aviation issues at the agency, told AFP.

The interference includes both spoofing (false positioning) and jamming (disruption of signals).

It was initially limited to the eastern areas of Sweden's airspace, over international waters.

But it has now "spread both geographically and in scope... occurring over a larger area over both land and sea in Sweden", Holmgren said in a statement.

"This is serious and is a security risk for civil aviation, not least given the extent, duration and nature of the interference," he added.

The jamming also affects maritime navigation and critical infrastructure using GNSS, the agency said.

In early June, Sweden and five other Baltic Sea countries -- Estonia, Finland, Latvia, Lithuania and Poland -- raised the issue with the Council of the International Civil Aviation Organization (ICAO), of which Russia is a member state.

The ICAO Council "expressed grave concern over the situation and demanded that Russia comply with its international obligations and ensure an immediate end to the interference", the agency said.

Despite this, the interference "in the Baltic Sea region has instead increased", it added.

The countries now intend to raise the issue with the ICAO's general assembly this autumn.

A plane carrying EU chief Ursula von der Leyen was hit by GPS jamming as it readied to land in Bulgaria on Monday, and Russia was suspected to be behind the incident, the European Commission said.

The plane was able to land safely.

The incident came as Western powers discuss new aid to Ukraine as it fends off Russia's invasion.