US President Barack Obama has issued a disaster declaration for the state of Louisiana, where at least five people have died and emergency crews have rescued more than 20,000 people stranded by unprecedented flooding.
Obama's announcement on Sunday came as John Bel Edwards, Louisiana's governor, said residents had been pulled from swamped cars, flooded homes and threatened hospitals across the southern part of the state.
The already soaked region is expected to get more rain from a storm system stretching from the Gulf Coast to the Ohio Valley.
|Officials say at least 20,000 have been rescued [Karim Haddad/Al Jazeera]
While the brunt of the storm that brought torrential rains was moving west towards Texas, Louisiana residents are told to remain cautious.
"Even with the sunshine out today intermittently, the waters are going to continue to rise in many areas, so this is no time to let the guard down," Edwards said.
READ MORE: Dramatic footage captures flash flooding in Maryland
The initial declaration makes federal aid available in the parishes of East Baton Rouge, Livingston, St. Helena and Tangipahoa.
About 5,000 people had been forced to sleep in shelters overnight around the state on Saturday.
Colonel Michael Edmonson, of Louisiana State Police, said helicopters were transporting food and water to those still trapped by floods.
| Louisiana's governor has warned that waters may continue to rise [Karim Haddad/Al Jazeera]
About 1,700 members of the Louisiana National Guard have been deployed for rescue efforts.
Even as the state grappled with high waters, the National Weather Service forecast heavy rain from the Gulf Coast as far north as the Ohio Valley through Monday, with a threat of flash flooding.
A flash flood watch was in place until Monday morning for Houston, where rains killed at least eight people in late April.