On Monday evening, Copenhagen Airport of the Danish capital suspended incoming and outgoing flights due to drones flying in the area, Copenhagen police said.

According to law enforcement, two or three drones were spotted.

About three hours later, however, Copenhagen Airport announced on social media that it was resuming operations.

Police and other law enforcement agencies are investigating the matter.

Flight-tracking website Flightradar24 reported that at least 35 flights bound for Copenhagen had been diverted as a result of the airport's closure, BBC reports.

In Norwegian capital Oslo, a drone was also detected near the main airport on Monday evening, Norwegian police confirmed to local media outlet NRK.

A spokesperson for the airport told public broadcaster NRK that airspace above the airport was closed at 00:00 local time due to "drone observation," and all flights would be diverted to the nearest airport.

And at around 04:30 local time, the spokesperson said Oslo Airport had been reopened.