(CNN) -- A fire swept through a hotel early Friday in a resort in the northern Philippines, killing six people including some U.S. citizens.
Two Americans, one South Korean and another foreigner whose nationality is yet to be established are among the dead, the owner of the hotel, David Fischer, said by phone. Authorities had initially suggested three Americans were believed to be among the dead.
Fischer said the fire began around 2 a.m. local time on the ground floor of the Dryden Hotel, which is in a nightlife district of Olongapo City, the site of a former U.S. Naval base situated west of the Philippine capital, Manila.
The flames destroyed seven bedrooms, as well as a set of offices, a communications center and a computer room, he added.
The six victims were all killed by smoke inhalation, according to Fischer, five of them in their rooms and one in the process of trying to escape.
Investigators are still looking into the cause of the blaze, but Fischer said initial signs suggested it may have been an electrical fire.
Police are trying to identify the victims' remains, as their identification documents were burned in the fire, said a local fire investigator, Jose Borlagdatan.
CNN's Brian Walker and Jessica King reported from Atlanta, Georgia. CNN's Kathy Quiano in Jakarta, Indonesia, contributed to this report.