Swedish morning newspaper Dagens Nyheter reported that Tuesday's fire on the Zenith, a Pullmantur Cruises ship docked in Stockholm, was started by two welders doing work at the front end of a lower deck.
The two men unsuccessfully tried to bring the fire under control themselves and ended up going to the hospital for smoke inhalation.
The newspaper added that the ship left Stockholm on Wednesday en route to Tallin, Estonia, instead of last night.