Denmark's prime minister said on Tuesday that the mysterious drones that flew over Copenhagen's airport for hours the evening before, forcing the hub to close, were a grave attack on key infrastructure.
"What we saw last night is the most serious attack on Danish critical infrastructure to date," Prime Minister Mette Frederiksen said in a statement, adding the attack aligned with the recent trend of "other drone attacks, airspace violations, and hacking attacks on European airports."
The Danish police earlier said they did not know who was behind the drones, but that evidence suggested it was a "capable actor."
The police that whoever was responsible for flying large drones over Copenhagen airport appeared to have been knowledgeable, as flights resumed in Denmark and Norway capitals following a night of travel chaos.
Airports in Copenhagen and Oslo reopened on Tuesday, hours after unidentified drones in their airspace caused dozens of flights to be diverted or cancelled, disrupting thousands of passengers.
Heavy travel delays were expected to last throughout Tuesday.
Copenhagen police inspector Jens Jespersen told reporters that "the number, size, flight patterns, time over the airport. All this together ... indicates that it is a capable actor. Which capable actor, I do not know."
He said "several large drones" flew over the Copenhagen airport for more than three hours late on Monday.
