Cyberattack halts work on Fehmarn Belt tunnel between Denmark and Germany
Employee ID cards and offshore equipment at the Fehmarn Belt tunnel site stopped working after a cyber incident, according to the investor. Sund & Baelt says it is in dialogue with contractor FLC, and no one has yet been identified as behind the attack.
What happened
The Femern Link Contractors consortium (FLC), which is building the Fehmarn Belt tunnel between Denmark and Germany, has been hit by a "cyber incident", according to the investor Sund & Baelt, which announced it on Tuesday, 13 October 2026. The Danish newspaper Folketidende reported that employee identification cards stopped working and that ships, cranes and platforms used for offshore work were immobilised. Danish media report a complete halt to work on the site, with specialist equipment not functioning. Sund & Baelt's representative Jens Villemoes said in a statement that a "cyber incident" had occurred and that dialogue with FLC about the situation is ongoing. Neither the investor nor the reports identify who is behind the attack or how long its effects will last.
- Consortium says the original 2029 opening date is unlikely to hold because of delays
- Danish officials warn of serious Russian hybrid attacks and the cyber threat level is raised from medium to high
- Sund & Baelt announces a cyber incident that has halted work at the FLC site
Suspicions of hybrid warfare
Henning Mortensen, chair of Denmark's Digital Security Council, told TV 2 that the matter may be connected to hybrid warfare, and he does not rule out such a link. The warning follows a late-September statement by Defence Minister Jeppe Brus and Thomas Ahrenkiel, head of Danish military intelligence, who said that serious hybrid attacks and other incidents from Russia should be expected. At that time the Danish Agency for Public Safety raised the cyber threat level from "medium" to "high". Cybersecurity specialist Jacob Herbst told TV 2 that artificial intelligence makes large-scale attacks easier to carry out at relatively low cost. He added that many organisations cannot keep pace with closing security gaps. No source names a suspect or a state behind the incident.
Impact on the site and workers
FLC employs 2.8 thousand people from companies in Denmark, Germany, France, Belgium and the Netherlands. According to Danish media, workers cannot use their access cards, and a considerable group of the workers on site are Poles. Sund & Baelt's representatives confirmed that talks with the contractor are under way, but they have not said how long it will take to remove the effects of the attack. No timetable for restoring work has been given.
The project and its delays
The Fehmarn Belt tunnel is an 18-kilometre road and rail crossing made of 89 concrete elements that are submerged in the sea. The modules, each 217 metres long, are produced in a temporary factory in the port of Roedby, transported by ships and platforms, and joined with high precision using digital software. The project's cost is estimated at about 7 billion euros. In autumn 2025 the consortium said the original 2029 opening date was unlikely to hold because of delays. No article says how the cyber incident will affect that timetable.
