A missile launcher which “cannot be deactivated” has prompted the Danish military to close the Great Belt strait, a route used by cargo ships to access the Baltic Sea.

A mishap involving a missile launcher on a Danish navy ship has halted traffic at one of the world’s busiest sea lanes on Thursday.

An area of the Great Belt strait was closed to air and sea traffic after a missile launcher malfunctioned during a Danish naval exercise.

“The problem occurred during a mandatory test where the missile launcher is activated and cannot be deactivated,” Denmark’s military said in a statement.

“Until the missile launcher is deactivated, there is a risk that the missile can fire and fly a few kilometers away,” the military added.