Searchers comb the Dan River in North Carolina after three people died and two went missing in a dam in North Carolina.

A group of nine people, who are believed to be part of the same family, was floating down the Dan River on inflatable tubes and went over a dam that's about 2.5m high next to a Duke Energy plant on Wednesday night, Rockingham County Emergency Services director Rodney Cates told reporters.

A Duke Energy employee who saw some of the tubers called the situation into 911 Thursday afternoon, and four were rescued that day. Three tubers' bodies were also found Thursday.

Cates said the rescued tubers spent the night floating in the water near the dam before they were found clinging to the tubes. He said they managed to stay afloat for about 19 hours, describing them as "very, very fatigued" when they were found.

The four were taken to a hospital and were expected to survive.

Cates said the search for the two still missing was being suspended late Friday afternoon and would resume Saturday. He said he was still optimistic the two missing tubers could be found alive.