Danish Prime Minister Mette Frederiksen said Tuesday she “cannot rule out in any way that it is Russia” behind the Monday night drone incursion that forced Copenhagen Airport to shut down for four hours.

Mette Frederiksen also told the Danish media that “what we saw last night is the most serious attack on Danish critical infrastructure to date.

Frederiksen also told the Danish media that “what we saw last night is the most serious attack on Danish critical infrastructure to date.”

When asked about a possible motive, she said: "The obvious . To see how far you can go and test the limits."

Russia denounced any accusation that it might be involved.

“We hear unfounded accusations from them every time,” said Kremlin spokesperson Dmitry Peskov, according to the Interfax news agency

Danish PM doesn’t rule out Russian involvement in airport drone ‘attack’

Mette Frederiksen says motive could be: “To disrupt and create unrest . “Perhaps a party that takes a serious, responsible stance should not make such unfounded accusations again and again.”

At a press conference, Flemming Drejer, director of operations at Denmark’s PET intelligence service, said that national authorities are looking in all directions for a cause.

“But it is clear that, given the current threat and what we are seeing on the international scene, this is something we are aware of,” Drejer said in response to a question about Russia.

Russia sent drones over Poland earlier this month, several of which were shot down, as well as over Romania . To cause concern . To disrupt and create unrest . .