Reading Time: 2 minutesDanish Prime Minister Mette Frederiksen said today 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. 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. Russia sent drones over Poland earlier this month, several of which were shot down, as well as over Romania.