"The first officer was piloting the ship this morning in heavy fog and there was another barge/ship that was apparently sideways," a guest told legal blog, Cruise Law News.
The Viking Kvasir is a 443-foot long ship with accommodation for 190 passengers and 50 crew.
The incident happened at 6:50AM, local time while most guests were still in bed. The first thing they felt was a jolt of engines being thrown into full reverse, followed by "a massive crash and the sound of breaking glass in our room".
Maritime Lawyer Jim Walker wrote that the ship claimed to have video proof that the other vessel was at fault.
The other ship was not identified.
The Hotel Manager said that everything had been done by the first officer to avert collision and that the crew suffered only minor injuries. One crew member was reportedly treated for burns and another for minor cuts, as the collision had occurred during a busy breakfast prep-time for guests.
This is the sixth incident involving Viking River cruises in the last six years, with the latest involving Viking Hermod in July this year.