Record rainfall left large areas of the US southeast under water Sunday as roads were closed and residents were warned to stay indoors.

The states of North and South Carolina have been particularly hard hit by heavy flooding, but the driving rain in recent days has spared almost none of the US East Coast.

The wild weather was blamed for at least four deaths in the Carolinas since Thursday.

The storms are part of a weather system separate from Hurricane Joaquin, which was downgraded to a Category Two storm as it headed toward Bermuda.

"We haven't seen this level of rain in the low country in 1,000 years," South Carolina Governor Nikki Haley said at a press briefing, urging people to stay inside to keep safe.

"This is not something to be out taking pictures of. This is not something that you want your kids playing in. The water is not safe.

"And a lot of areas across the state where you see this deep water, it's got bacteria in it. So stay inside and don't get in there," she stressed.

"This is an incident we've never had before."

President Barack Obama has issued an emergency declaration for the state, ordering federal aid for areas affected by flooding.

- Historic Charleston submerged -

Streets were submerged in the historic old town of Charleston, South Carolina, as non-stop rain battered the city, with flooding closing restaurants and bars.

"Right now, we are in life-saving mode," said Lieutenant Colonel Cindi King, a spokeswoman for the South Carolina National Guard.

"We are just focusing on helping our citizens."

The National Weather Service said the city had seen 14 inches (36 centimeters) of rain over the past three days, beating a previous record of 12 inches in 1973.

"It's the worst water I have seen in the 10 years I have lived here. Neighbors tell me it's the worst since Hurricane Hugo" in 1989, said 38-year-old Jamieson Clair, a resident of the city.

In hard-hit Columbia, the mayor ordered a curfew for the city from 6:00 pm to 6:00 am.

The Red Cross has opened 26 shelters across the state.

The University of South Carolina, based in Columbia, canceled all Monday classes.

More than 200 swift-water rescues have been reported since Saturday night, while the state's Department of Transportation said at least 211 state roads and 43 bridges were closed due to flooding.

The National Weather Service warned of "potentially historic and life-threatening flooding" across the southeastern United States.

- Bermuda under threat -

Forecasters said Joaquin now is closing in on tiny Bermuda, with a population of just 66,000, where the potential damage could rival what was seen in the Bahamas.

The storm still has winds of 100 miles (160 kilometers) per hour, and is dumping heavy rain.

In the Bahamas, a low-lying archipelago, residents surveyed the damage after Joaquin destroyed homes and left some without power or phone services.

The Bahamas is home to 385,000 people and visited by far more tourists every year -- about 1.3 million.

- Search for cargo ship -

Rescuers were still frantically searching for the El Faro cargo vessel, with which contact was lost early Thursday as the dangerous weather system approached the Bahamas.

Coast Guard troops turned up "a number of different objects in the water" via an aerial search but were unable to confirm whether they were from the vessel.

"We found a few life rings, life jackets and there's been a report of possible oil sheen," Coast Guard Chief Petty Officer Ryan Doss told AFP.

"We have boats in the water... they will be able to get to some of that stuff soon" he said, adding that it was "the first day of good weather and the seas are down one or two feet (one-third to one meter)."

Tim Nolan, president of the company that owns the El Faro, said it had sent its only other ship plus a tugboat in search of the missing vessel and had recovered "a container, which appears to be from the El Faro, and observed what appears to be an oil sheen."

En route from Florida to Puerto Rico, the 735-foot cargo ship was reported to be caught in the storm near Crooked Island, part of the Bahamas island chain.

It was from there that it sent a satellite notification stating the ship had lost propulsion and had a 15-degree list.

Twenty-eight Americans and five Poles were on board.