Nato to step up vigilance in Baltic Sea region after drones spotted over military bases

Move comes after new drone sightings near major military installations in Denmark and Norway

Nato has vowed to upgrade its mission in the Baltic Sea after Denmark's armed forces said unidentified drones were seen near the country's military installations overnight.

There have also been several drone incursions near airports and other critical infrastructure this week, with Copenhagen's airport closed for several hours late on Monday as several drones were seen in its airspace.