Relatives of crew members wave with Danish flags as the frigate HDMS Iver Huitfeldt (F361) of the Royal Danish Navy arrives at the Naval Base in Korsoer, Denmark on April 4, 2024.

An activated but faulty missile launcher on a Danish navy vessel triggered a closure of airspace and shipping traffic in the Great Belt strait on Thursday, the Danish armed forces said.

Denmark's National Maritime Authority had earlier warned ships not to sail through the Great Belt strait, one of the world's busiest sea lanes and the main maritime access to the Baltic Sea, due to the risk of "falling missile fragments".