COPENHAGEN, Denmark — Norway’s prime minister says World War II saboteur Joachim Roenneberg, who headed the four-man team that blew up a plant producing heavy water which Nazi Germany could have used to produce nuclear weapons, is dead at 99. 
 
 Prime Minister Erna Solberg says Roenneberg was “one of our finest resistance fighters” whose “courage contributed to what has been referred to as the most successful sabotage campaign” in Norway. 
 
 Roenneberg, then 23, was tapped by the SOE — Britain’s wartime intelligence-gathering and sabotage unit — to destroy key parts of the heavily guarded plant in southern Norway in February 1943. 
 
 The operation — during which not a single shot was fired — has been recounted in books, documentaries, films and TV series. 
 
 Solberg wrote Sunday on Facebook hours after Roenneberg’s death. ||||| FILE - In this Thursday, April 25, 2013 file photo, Norwegian war hero and resistance fighter Joachim Roenneberg holds a Union flag as he walks in a park near the Palace of Westminster, after receiving... (Associated Press) 
 
 FILE - In this Thursday, April 25, 2013 file photo, Norwegian war hero and resistance fighter Joachim Roenneberg holds a Union flag as he walks in a park near the Palace of Westminster, after receiving the Union Jack Medal for his efforts and cooperation with the British during the second World War.... (Associated Press) 
 
 COPENHAGEN, Denmark (AP) — Norway on Monday mourned World War II saboteur Joachim Roenneberg, who headed a five-man team that daringly blew up a plant producing heavy water, depriving Nazi Germany of a key ingredient it could have used to make nuclear weapons. 
 
 Prime Minister Erna Solberg said Roenneberg, who died Sunday at 99, was "one of our finest resistance fighters" whose "courage contributed to what has been referred to as the most successful sabotage campaign" in Norway. 
 
 Roenneberg, then 23, was tapped by the Special Operations Executive, or SOE — Britain's war-time intelligence gathering and sabotage unit — to destroy key parts of the heavily guarded plant in Telemark, in southern Norway, in a raid in February 1943. 
 
 In a 2014 Norwegian documentary in connection with his 95th birthday, Roenneberg said the daring operation went "like a dream" — a reference to the fact that not a single shot was fired. 
 
 Parachuting onto snow-covered mountains, the group was joined by a handful of other commando soldiers before skiing to their destination. They then penetrated the fortress-like heavy-water plant to blow up its production line. 
 
 Roenneberg said he made a last-minute decision to cut the length of his fuse from several minutes to seconds, ensuring that the explosion would take place but making it more difficult to escape. The group skied hundreds of kilometers (miles) across the mountains to escape and Roenneberg, wearing a British uniform, ended up in neighboring neutral Sweden. 
 
 Operation Gunnerside has been recounted in books, documentaries, films and TV series, including "The Heroes of Telemark," starring Kirk Douglas and Richard Harris. 
 
 "We must not forget what he stood for and has passed on to us," said Eva Vinje Aurdal, mayor of his hometown of Aalesund, 380 kilometers (235 miles) northwest of the capital, Oslo. 
 
 The town ordered flags to fly at half-mast Monday and flowers were laid at the foot of a sculpture of Roenneberg, showing him in a uniform, walking up a rocky path. Inaugurated in 2014 by Roenneberg, the granite monument carries the names of all the men who took part in the World War II raid. 
 
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 This story has been corrected to the team consisted of five men, not four.
– It was said to be a "near-suicide mission," and a previous attempt saw dozens of men killed and captured by the Nazis. But the "Operation Gunnerside" raid in World War II on a Norwegian plant making heavy water—a hydrogen-filled substance that could eventually have been used by Germany to make atomic bombs—was a successful one, led by 23-year-old Joachim Roenneberg, the youngest member of the five-man operation. The plant was blown up that day in February 1943, becoming what Norway Prime Minister Erna Solberg calls "the most successful sabotage campaign on Norwegian soil during the war," per the New York Post. Tributes are once more being paid to Roenneberg as Norwegian officials on Sunday announced his death at age 99, Reuters reports. The raid on the Norsk Hydro plant, which was surrounded by guards, is one of legend that's since been the subject of books, movies, and a TV series. The team put together by a British espionage and sabotage agency parachuted onto a mountain near the plant, joined up with some commandos, skied their way to their target, and broke into the plant, where they blew up the heavy-water production line. Making the raid especially notable was that not a single gunshot was fired; in a 2014 documentary, Roenneberg said the attack went off "like a dream," per the AP. The team then fled on their skis, with Roenneberg escaping over the border to neutral Sweden. "He was one of our top insurgents during the war," Solberg posted on Facebook, adding to the NTB news agency, via Reuters: "He is one of our great heroes." (A Soviet officer may have saved the world from nuclear war.)