Six of the students killed and the six injured in the early morning fire in Ocean Isle Beach were students at the University of South Carolina, according to officials at the university.

The seventh fatality is believed to be a Clemson University student.

"This is a very sad day for the University of South Carolina family," said Dennis A. Pruitt, the vice president for student affairs.

Six survivors were hospitalized and released, including one who jumped from the burning home and into a waterway, Ocean Isle Beach Mayor Debbie Smith said.

"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."

The cause was being investigated. She said the house had working smoke detectors.

Police in Ocean Isle Beach, North Carolina, received an emergency call at 7:01 a.m. EDT, the town said in a statement. When rescue services got there two minutes later, the house was completely engulfed in flames, according to the statement.

Newspaper deliveryman Tim Burns, who called 911 after seeing a column of smoke rising from the house, said he tried to approach the door but the flames were too intense.

"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 don't think I've ever felt as helpless in my life."

Smith said officials had not yet contacted all the victims' families, and that they were not yet releasing their names.

Ocean Isle Beach is a popular resort destination along the southern coast of North Carolina. It has about 425 year-around residents, according to its website.