Flooding in Louisiana submerged large parts of the region on the US Gulf Coast on Sunday, three days after water-swelled streams and rivers began overflowing. At least five people have died and emergency crews have rescued more than 20,000 people stranded by the rising waters.

After speaking to Louisiana Governor Jon Bel Edwards on Sunday, President Barack Obama issued a disaster declaration for in the flood-hit region.

"This is a serious event," Governor John Bel Edwards said of the "historic" record floods.

"I have traveled to affected areas and have seen the destruction caused by this unprecedented flooding," he said.

Even as the rain begins to decrease, Edwards said the situation was still "ongoing." "This is not over," he said.

Under the disaster declaration, emergency federal funding will be made available to support rescue crews who have been working non-stop over the weekend.

The heavy rains began Friday, with between six and 10 inches (15 to 25 centimeters) of rain falling on parts of southeast Louisiana. Several more inches fell on Saturday.

Most of the flooding has been around the capital Baton Rouge. In nearby Livingston Parish, thousands of people were evacuated, with 100 people still waiting for help. Almost 500 people and 61 pets were also rescued by the Louisiana National Guard, including 15 by air.

According to the White House, more than 7,000 residents have been rescued from their homes and cars.

The US National Weather Service issued flash flood warnings extending from the Texas coast to the Ohio River Valley on Sunday. Central and northern Louisiana, as well as southern Texas, were expected to see heavy rain for several days.

ksb/se (AFP, Reuters)