( CNN ) -- Six of the seven college students killed in a massive house fire Sunday morning in Ocean Isle Beach , North Carolina , attended the University of South Carolina , a university official said Sunday . `` This is a very sad day for the University of South Carolina family , '' Dennis A. Pruitt , the vice president for student affairs , told reporters . The seventh fatality is believed to be a Clemson University student , he said . The six survivors -- who were treated and released from Brunswick Community Hospital -- are also USC students , he said . Pruitt said the bodies were being sent to Chapel Hill , North Carolina , for identification . Watch home video showing the house in flames » . `` It is difficult to ascertain exactly who was in the house and who was not , '' Pruitt said , explaining that several area houses were filled with college students visiting for the weekend . Newspaper deliveryman Tim Burns was aghast when he first saw the inferno early Sunday morning . He tried to approach the door but the flames were too intense , he told the Associated Press . `` When I was going up to the entryway , you could hear the windows above me explode , '' Burns said . `` When I knew the flames had taken over , I do n't think I 've ever felt as helpless in my life . '' The USC students were affiliated with the Delta Delta Delta sorority and the Sigma Alpha Epsilon fraternity , Pruitt said , although he stressed that the weekend was not an official Greek function . `` It just so happens , as on many university campuses , that certain sororities and certain fraternities hang around together , '' he said . One person described as `` unaccounted for '' was later confirmed dead , Ocean Isle Beach Mayor Debbie Smith told CNN . `` We suffered a terrible tragedy at Ocean Isle this morning , '' Smith said in a news conference . `` Nothing like this has ever happened at Ocean Isle Beach , and we hope it never will again . '' She said officials had not yet contacted all the victims ' families , and that they were not yet releasing their names . The mayor said one of the 13 people in the house was related to the house 's owner . Smith said the house was fully `` engulfed '' in flames around 7 a.m. when the fire department arrived on the scene , about five minutes after the fire department was notified . She said the house had working smoke detectors , AP reported . Officials are investigating the cause of the fire , Smith said . `` We ran down the street to get away , '' Nick Cain told the AP . The University of North Carolina student was staying at a house about 100 feet away . Some of his friends had met several people staying at the house that burned down . `` The ash and the smoke were coming down on us . We were just trying to get away , '' Cain told the AP . Ocean Isle Beach is a popular resort destination along the southern coast of North Carolina . The 7-mile-long island 's year-round population is about 425 , while the summer season population is about 25,000 , according to the town 's Web site . E-mail to a friend .
Six of the dead in fire were University of South Carolina students . Official : Two dead at hospital and released were also USC students . Mayor Debbie Smith said one of 13 at house is related to owner of house . Victims ' are not being released until police are notified .