A minehunting force of ships from five NATO countries has found more than 30 unexploded bombs and mines dating back to World War II during a two-week search in the waters off Oslo.
The minehunters scoured stretches of the 96-kilometre fjord leading to Norway's capital to ensure the waters are safe, 75 years after the war's end.
During the German occupation of Norway, the inlet was heavily mined, and bombers also dumped their payloads into the fjord.
NATO's Standing Minecountermeasures Group 1 – charged with safeguarding northern European waters and ensuring they are mine-free – regularly conducts concerted "historic ordnance disposal" operations, both in Oslofjord and off the coast of the Baltic States whose waters were similarly heavily mined and peppered with bombs during the conflicts of the 20th Century.
In the two-week-long effort in Oslofjord, ships from the navies of Germany, the Netherlands, Norway, Belgium, and the UK located 38 pieces of ordnance, with 18 alone being found by the crew of the Royal Navy Sandown-class minehunter HMS Grimsby.
Grimsby's discoveries in the fjord include 15 British air-dropped mines and three British bombs.
However, detonating the ordnance was deemed unsafe due to the risks it posed to the marine environment and nearby communities. Instead, the locations of the ordnance were pinpointed and passed on to the Norwegian authorities who will update their charts and issue warnings accordingly.