AMSTERDAM (Reuters) -The car carrier burning off the Dutch coast since Tuesday night is carrying nearly 500 electric vehicles, ship charter company "K" Line said on Friday, significantly more than the 25 initially reported by the coastguard. There were 3,783 vehicles on board, including 498 battery electric vehicles, a Tokyo-based spokesperson for K Line (Kawasaki Kisen Kaisha), which had chartered the vessel, said. The coastguard said on its website Thursday the cause of the fire was unknown, but an emergency responder is heard in a recording released by Dutch broadcaster RTL saying "the fire started in the battery of an electric car".