COPENHAGEN: Unidentified drones flew over Danish military sites including its biggest base following a slew of earlier sightings that Copenhagen has termed a `hybrid attack`, hinting at possible Russian involvement.

Neighbouring Norway was also investigating `possible sightings of drones` early on Saturday near its biggest military base, Orland, where its F-35 fighter jets are parked.

Mysterious drone sightings across Denmark and Norway since Monday have prompted the closure of several airports.

Copenhagen will host a European Union summit gathering heads of government on Wednesday and Thursday and Denmarkhas accepted a Swedish offer of Stockholm`s anti-drone technology to ensure the meeting can proceed without disruption.

In Denmark, drones were confirmed at `several military sites`, a military spokesman said on Saturday, refusing to provide other details.

Danish police said `one to two drones` were observed on Friday around 8:15pm (1815 GMT) near and over the Karup military base, the country`s biggest base which houses all of the armed forces` helicopters, airspace surveillance, flight school and support functions. Karup is also home to parts of the defence command.

Police spokesman Simon Skelkjaer saidhe could not comment on where the drones came from, adding: `We didn`t take them down.` Police were cooperating with the military in their investigation, he said.

The Karup base shares its runways with the Midtjylland civilian airport, which was briefly closed, though no flights were affected as none were scheduled at that hour, Skelkjaer said. In Norway, the military was joining forces with police to determine if it was indeed drones that were observed.

`The sightings are probably drones but the investigation will find out what it was.

As of now we`re handling it as a drone sighting,` a spokesman for Norway`s joint headquarters, Brynjar Stordal, said.`At least two drones` flew in a restricted area near the base `for around an hour` before they disappeared, he said. `They were not engaged by us.` Police in Norway`s northern Nordland county said they were temporarily extending air and land restrictions for drones and other unmanned aerial vehicles to 10 kilometres (6.2 miles) around four airports serving a mix of regional, international and military flights, until Monday at midday.

In a statement, police said the move was `a precautionary measure` and said no drones had been observed in the region on Saturday.

Drone sightings in Nordic countries earlier in the week following drone incursions inPolish and Romanian territory and the violation of Estonian airspace by Russian fighter jets, which raised tensions in light of Russia`s ongoing invasion of Ukraine.

Russia to blame? Danish Prime Minister Mette Frederiksen said that `over recent days, Denmark has been the victim of hybrid attacks,` referring to unconventional warfare. Investigators have so far failed to identify those responsible, but Danish Defence Minister Troels Lund Poulsen said Thursday the flights appeared to be `the work of a professional actor`. Frederiksen has pointed the finger at Russia.-AFP