Rescuers made contact Monday with four crew members stuck inside a South Korea-owned cargo ship that overturned and caught fire near a major port in Georgia over the weekend, said the U.S. Coast Guard, adding that officials are working to free the quartet from the massive vessel.

The Golden Ray, a 656-foot vehicle carrier, listed "heavily" and then rolled over on its side early Sunday in St. Simons Sound near Brunswick, Ga., according to the Coast Guard.

Rescuers drilled a hole overnight through the ship's hull and made contact with the four crew members, who had been listed as missing.

"Extraction being planned," the Coast Guard tweeted.

Coast Guard rescuers were able to find the four South Korean crew members by rappelling down the side and drilling a hole through the hull to contact them, Lt. Lloyd Heflin told The Associated Press. Heflin added the rescue team is communicating with the trapped sailors through the hole they drilled, but getting them out remains quite challenging.

"The early indication is they are on board and OK," Heflin said.

Coast Guard Southeast said on Twitter it's developing a plan to extract the crew members, but that "this is a slow, but safe process" and that rescuers will deliver supplies through a hole drilled in the upturned hull of the Golden Ray.

RESCUE CREWS SEARCH FOR CREW MEMBERS ABOARD OVERTURNED CARGO SHIP, CONCERNS ABOUT STABILITY

In the hours before the Coast Guard announced all crew members were alive, South Korea's Foreign Ministry said that the four crew members were in the engine room of the overturned cargo ship and were stuck in the shipping channel awaiting help from a rescue team.

On Sunday, Coast Guard Capt. John Reed said 20 people were safely evacuated from the ship before rescuers determined the smoke and flames and unstable cargo made it "too risky" to venture further inside. Reed said the fire was observed off the ship's starboard side and produced black smoke.

The foreign ministry's statement also said the fire that prevented a rescue attempt is now extinguished.

South Korea also said some of the missing South Koreans "apparently tapped back three times" after Coast Guard staff tapped on the hull. A Coast Guard spokesman told the AP on Monday morning that rescuers heard noises but initially couldn't confirm they were signs of life without getting inside the overturned ship.

The Coast Guard posted video on Monday of salvage crews assessing the Golden Ray's hull for a possible entry.

"Once salvage professionals have determined the vessel to be stable, we will identify the best option to continue our rescue efforts for the four crew members who remain on board," Reed said during a news conference Sunday afternoon in which he detailed how the Coast Guard was trying to safely get inside.

CARGO SHIP OVERTURNS NEAR GEORGIA PORT, 4 CREW MEMBERS MISSING, COAST GUARD SAYS

Petty Officer 3rd Class Ryan Dickinson told the Associated Press it is not known if weather conditions caused the ship to lurch. Hurricane Dorian brushed past the Georgia coast last week before being downgraded to a post-tropical cyclone. Dickinson said it was not immediately known whether there were any injuries on board.

Cmdr. Norm Witt, Commander of Coast Guard's Marine Safety Unit in Savannah said at Sunday's afternoon news conference that the incident remains under investigation, and so far the stricken ship does not appear to be a pollution hazard to area waterways. Officials, however, are putting together a pollution mitigation plan in case something changes.

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The ship, a vehicles carrier, was built in 2017 and sails under the flag of the Marshall Islands, according to the vesselfinder.com. The ship's registered owner is a South Korean company.

The Port of Brunswick is currently closed to vessel traffic, with an established emergency safety zone in St. Simons Sound. Vessels are not authorized within a half-mile of the Golden Ray, which was lying on its side.

The Port of Brunswick is a major deepwater port in Georgia, which is comprised of three terminals that makes up the facility, according to the Georgia Ports Authority.

"The port’s well-earned reputation for productivity and efficiency is heightened by its position as one of the fastest-growing auto and heavy machinery ports in North America," the GPA's website states. "Today, more than 12 major auto manufacturers, supported by three auto processors, utilize the Colonel’s Island Terminal."

The port is one of the busiest U.S. seaports for shipping automobiles. Nearly 614,000 vehicles and heavy machinery units moved across its docks in the 2019 fiscal year that ended June 30, according to the Georgia Ports Authority.

The Associated Press contributed to this report.