A large fire broke out late Friday night in the facilities of Volvo Penta on the island of Hisingen in Sweden and investigators were classifying it as arson during the early stages of the investigation.
"It didn't burn the entire facility, but the whole plant has been affected by smoke," Bosse Andersson, of the emergency services in greater Gothenburg, told the TT news agency on Sunday.
Police said three people were in the factory when the fire started, but they fled when the alarm was raised. For investigative reasons, the incident is currently classified as an arson.
Firefighters were forced to take a step back from quelling the flames when an attempt to remove a section of the roof with a crane failed.
"The roof collapsed and folded like a lid," Joakim Hallin, of the local emergency services, told the news outlet.
Rescue services eventually brought the blaze under control and were expected to maintain a presence at the facility throughout the day on Sunday.
Police cordoned off the area around the plant to conduct a technical examination of the scene, but were unclear about why the blaze occurred.
"We really don't have any notion as to what started the fire as things are at present," said Peter Adlersson, of the Västra Götaland police. The whereabouts of the three people who fled were not known on Sunday.
Emergency services discovered large cracks in the concrete foundation supporting the 15,000-square-meter building, according to the Göteborgs-Posten. First responders and Volvo Group employees were trying to save as much of the materials inside the building as possible on Saturday. The alarm came shortly after midnight Saturday morning. When the emergency services arrived, the fire was fully developed.
The building is about 50 to 100 meters long and has three to four levels. It is not yet known exactly how much damage occurred, but the emergency services said the whole building was affected.