CONWAY, S.C. – Two people being transported in a sheriff’s office van in South Carolina died Tuesday when the vehicle was overcome by floodwaters, the Horry County Sheriff's Office confirmed.

The vehicle, staffed by two Horry County deputies, was transporting two detainees from Conway to Darlington and was traveling west on Highway 76 around a half mile from the Little Pee Dee River when the vehicle was overtaken by flooding from Hurricane Florence, according to an emailed statement from the sheriff's office.

The two deputies "attempted to extricate the persons being transported," the agency said in its statement.

The Associated Press reported the detainees were two women. Their names have not been released.

More:Florence aftermath: Flooding leaves residents seeking food, water

"Despite persistent and ongoing efforts, floodwater rose rapidly and the deputies were unable to open the doors to reach the individuals inside the van," the sheriff's office's statement said.

High-water rescue teams arrived and were able to rescue the two deputies from the top of the van, according to the statement.

"At this time, the recovery effort is ongoing, and the transportation vehicle cannot be removed due to rising waters and dangerous conditions," the sheriff's office said.

The two individuals being transported were confirmed dead by the Marion County coroner.

Thom Berry, a spokesman for the State Law Enforcement Division, said SLED agents have been sent to the scene to investigate.

"Tonight's incident is a tragedy," said Horry County Sheriff Phillip Thompson. "Just like you, we have questions we want answered. We are fully cooperating with the State Law Enforcement Division to support their investigation of this event."

The death toll from Florence reached at least 37 in three states Tuesday, as Florence went in two directions: Water flowed downstream toward the Carolina coast, and storms hit the Northeast, where flash floods struck New Hampshire and New York state.

Aides say President Donald Trump will visit North Carolina on Wednesday to see the damage from Florence.