The Danish military was forced to temporarily close a major shipping lane and nearby airspace after a missile launcher onboard a ship malfunctioned.
The National Maritime Authority issued a warning for vessels to avoid part of the Great Belt strait off the coast of Denmark on Thursday afternoon due to a risk of “falling missile fragments”.
A naval exercise began in the area last month and is due to end on Friday.
The shipping lane was reopened on Thursday evening after about six hours.
In a statement, the Danish military said the problem with the missile occurred “during a mandatory test where the missile launcher is activated and cannot be deactivated”.
“Until the missile launcher is deactivated, there is a risk that the missile can fire and fly a few kilometres away,” the military added.
The missile was launched from the Niels Juel frigate, which has been part of Nato’s standing naval force since 2023.
The warning covered an area south-west of the town of Korsor, some 4km (2.5 miles) south of the Great Belt bridge, which crosses the strait.
The bridge remained open to traffic, its operator said.
The defence ministry said the missile contained 150kg of explosives, adding that it was not armed and would not detonate if it crashed into the sea.
In a later statement, the ministry said specialists had “carried out a number of different tests after which it was established that the booster was not armed and that there is no longer a risk that the missile can be launched”.
The incident in the Great Belt strait comes at the end of a difficult week for the Danish navy.
On Wednesday, the chief of defence, Gen Flemming Lentfer, was sacked for failing to report a malfunctioning weapons systems on a Danish frigate, the Iver Huitfeldt, in the Red Sea.
Denmark’s defence minister, Troels Lund Poulsen, said he had lost his trust in Mr Lentfer, who did not inform the defence ministry that the frigate’s radar and missile systems failed as it came under attack from a drone controlled by Houthi militants.
The Iver Huitfeldt was helping to safeguard commercial sea traffic from Houthi attacks as they launched a campaign of support for Palestinians following Israel’s offensive in Gaza.
Neither the crew nor the ship were harmed during the deployment.