Europe believes Russia is behind a spate of mysterious drone sightings across the continent but "can't prove it," Dutch Prime Minister Dick Schoof told the Kyiv Independent on Oct. 6.
Speaking during a visit to Kyiv, Schoof was asked if there was a consensus among European countries about who was responsible.
"Yes of course," he said, adding: "Unfortunately, we cannot prove who is behind it, but there's a lot of thinking that maybe it's the Russians, but we cannot prove it."
Over the last few weeks, drones have violated the airspace of at least eight European countries — Denmark, Lithuania, Finland, Estonia, Romania, Germany, Belgium and the Netherlands.
Several airports including the Netherlands' Schiphol Airport have been forced to temporarily halt flights. At Germany's Munich Airport on Oct. 2, when drone sightings grounded 17 flights and affected nearly 3,000 passengers.
Drones have also been sighted over military bases and energy infrastructure including the Karup Air Base in Denmark, and a power plant in Finland.
"I hope that one day we can prove either it's the Russians or it's something else," Schoof said, adding: "But it is really worrying that they are now around our infrastructure, around our airports, and I think we have to step up our security in that respect."
The wave of sightings has raised concerns amid heightened tensions between Moscow and NATO following a series of Russian airspace violations.
Speaking at the Valdai Discussion Club in Sochi, Russia, on Oct. 2, President Vladimir Putin mocked European concern over drone sightings.
When asked by a moderator, "Why have you sent so many drones to Denmark?” Putin laughed and replied, "I won’t do it anymore." He denied Russian involvement in recent drone activity and likened the sightings to UFO reports.
In September, Polish forces shot down several Russian drones that entered their airspace. Days later, a Russian drone breached Romanian territory, though Bucharest chose not to engage it.
President Volodymyr Zelensky said on Sept. 28 that intelligence reports indicate Russia's so-called "shadow fleet" of oil tankers is being used to "launch and control" Russian drones over European cities.