Also, it has been reported that approximately half of the passengers were evacuated into lifeboats and the others were able to remain on the ship until it reached port. I would note that while some of you may say, "Why didn't they all stay onboard?", you need to appreciate second (even less than minutes) matter. Until the enough of the situation is known, when there is a serious fire, the last place you want to be is on a burning ship. What is most important is that all of the passengers were safely evacuated by whatever means. (Yes, those dreaded muster before a cruise are for a good reason.)
While I do not know the cause of the fire, Hurtigruten confirms that the hull was not penetrated, but there is water infiltration (obviously from damaged piping, pumps and/or through-hull fittings as well as the water that was poured into the ship to suppress the fire). Large auxiliary pumps have been placed in those areas to avoid further damage and to prevent a previous concern that the ship might capsize. It is also reported that the ship is listing 10 degrees. From the photos below you can see what that looks like.
A good friend of mine has provided these remarkable photos which were, I am told, in the Norwegian newspapers: