John Bel Edwards, the governor of the state of Louisiana, has described the flooding as "unprecedented" and "historic."

"This is an ongoing event and we are still in the response mode," he told a press conference on Saturday. "This is a major disaster."

The governor declared a state of emergency in Louisiana on Friday after torrential rain overnight caused rivers and creeks to reach record heights, inundating roads and properties.

The National Weather Service said the severe weather had resulted in "catastrophic flash floods across Louisiana," with heavy rain and thunderstorms expected to continue into Monday.

Authorities said three people had died in floodwaters and searches were continuing for more victims. Emergency workers have rescued more than 1,000 people from flooded homes and cars since the deluge began.

Meanwhile, Entergy Louisiana reported that nearly 12,000 customers were affected by power outages overnight on Saturday.

Mississippi also at risk

Communities in the neighboring state of Mississippi were also affected by freak floods. The weather service said there was a threat heavy rain would continue to expand westward with "at least a slight risk of flash flooding tonight over a large area from the southern plains to the mid-Mississippi/Ohio valleys and even the northeast."

On Friday, rescue workers found the body of a 68-year-old man who drowned in floodwaters near Baker, Louisiana. Another body was recovered in the state's north, inside a pickup truck that had been swept off a highway near the town of Greensburg.

On Saturday, authorities said a woman died after her car was swept into Louisiana's Tickfaw River.

nm/cmk (AFP, dpa, AP)