The four remaining seafarers unaccounted for aboard the capsized car carrier 7,700-ceu Golden Ray (built 2017) have been pulled to safety, the US Coast Guard has confirmed.

Three of the missing crew members were safely extracted from the vessel at around 15:00 local time on Monday, while the fourth man did not emerge until almost three hours later.

The last man to be rescued had been trapped behind glass in an engine control room, according to the USCG's Captain John Reed, Sector Charleston commanding officer.

Reed said two of the three extracted seafarers were "very ambulatory", able to climb a ladder placed by rescue personnel.

Mission accomplished: The rescue team celebrate the recovery of the fourth trapped seafarer aboard the Golden Ray. Photo: US Coast Guard

"Their condition is relatively good for having spent 34 hours in the conditions they've been in," he said. "They were subject to very tough conditions."

He said the air temperature directly outside of a small hole cut by USCG personnel reached 49 degrees Celsius.

"It was even hotter on the inside," he said.

Among the initial 20 crew rescued from the vessel on Sunday were six South Koreans, 13 Filipinos and the US pilot, South Korea's foreign ministry said.

The incident took place early on Sunday morning at around 2am local time near Brunswick, in between Jacksonville and Savannah on the US east coast.

The vessel’s master and chief engineer are helping authorities and salvage teams to develop plans to stabilise the vessel and continue resumed rescue efforts.

USCG units involved in the response include two Brunswick response boat crews, two helicopters, a cutter and salvage engineering response team.

The cause of the incident is under investigation.

USCG pictures and reports suggest the Marshall Islands-flagged vessel suffered some form of internal fire.

While the search is ongoing, the Port of Brunswick has been closed, and ships are being kept back at least a half mile from the capsized car carrier.

The Georgia Department of Natural Resources, Moran Towing, SeaTow, Brunswick Bar Pilots Association and Glynn County Fire Department are assisting in the rescue operation.

Smoke can be seen coming from the 7,700-ceu Golden ray (built 2017). Photo: US Coast Guard