Russia’s embassy in Denmark on Thursday dismissed suggestions that Moscow was involved in a series of drone flights over the Nordic country this week, calling the unexplained incidents a “staged provocation.”

Danish police said that drones flew over multiple airports across the country on Wednesday night and caused one of them to close for several hours. Earlier in the week, Copenhagen Airport and Oslo Airport in Norway were also temporarily shut down after similar incidents.

While some Western officials, including NATO Secretary Mark Rutte, have cautioned that the source of the drone flights remains unclear, Danish Prime Minister Mette Frederiksen has suggested Russia could be involved, without making a direct accusation.

Russia’s embassy in Denmark claimed the drone flights would be “used as a pretext for further escalating tension in the interests of forces seeking by all means to prolong the Ukrainian conflict and extend it to other countries.”

“The Russian side firmly rejects the absurd speculations of involvement in the incidents,” the embassy said. It did not specify who it believed was behind the disruptions.

Danish authorities described the flights as a “hybrid attack” carried out by a “professional actor” designed to create fear and disruption, adding that they would acquire new capabilities to detect and intercept drones.

“There can be no doubt that everything points to this being the work of a professional actor when we are talking about such a systematic operation in so many locations at virtually the same time,” Danish Defense Minister Troels Lund Poulsen said at a press conference.

An investigation involving the Danish intelligence service and armed forces is ongoing to “clarify the circumstances,” Danish police said.

AFP contributed reporting.