Russia has rejected "absurd" speculation about its involvement in recent drone incidents in Denmark, its embassy in Copenhagen has said.
In a statement on Telegram, it described disruptions at Danish airports as a "staged provocation" and said they were being used as a pretext to escalate tensions.
A number of airports in western Denmark experienced disruption early this morning after after unidentified drones flew into their airspace overnight - the second such incident there this week.
Denmark's Prime Minister, Mette Frederiksen, said she had spoken with NATO chief Mark Rutte about the incident.
In a post on social media platform X, she said she and Mr Rutte discussed the "serious situation" and agreed that NATO would "work with Denmark on what we can do together to ensure safety and security".
Mr Rutte said the alliance was taking the incidents "very seriously" and was working to make sure key infrastructure was protected.
"NATO allies and Denmark are working together on how we can ensure the safety and security of our critical infrastructure," he said, also on X.
Denmark's defence minister has said the drones were a systematic and hybrid operation by a "professional actor".
"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," said Troels Lund Poulsen.
"This is what I would define as a hybrid attack using different types of drones."
Mr Poulsen said there is no direct military threat, but Denmark would reinforce its capacity to "detect" and "neutralise" drones.
Billund airport, Denmark's second biggest, was closed for an hour, and Aalborg, used for commercial and military flights, was closed for three hours due to drone incursions late last night, Danish police said.
Drones had also been observed near airports in Esbjerg and Sonderborg, as well as Skrydstrup airbase, home to some of Denmark's F-16 and F-35 fighter jets.
All five are located on the Jutland peninsula in western Denmark.
Resident Morten Skov told Reuters he saw green blinking lights coming from west of Aalborg airport, which "stood still right over" the facility.
Danish national police said the drones followed a similar pattern to ones that had halted flights at Copenhagen airport late on Monday and early Tuesday.
It described that as the most serious "attack" yet on its critical infrastructure and linked it to a series of suspected Russian drone incursions and other disruptions across Europe, without giving evidence.
Minister Poulsen said they do not have evidence to say there is a link to Russia.
Russia's ambassador to Denmark, Vladimir Barbin, denied any involvement by his country in the Copenhagen incident.
