Hurricane Harvey: Up to 2,000 Rescued as Houston Hit by 'Catastrophic Floods'
Storm Harvey continues to batter Texas with heavy rains.
There are reports of possible deaths in submerged vehicles, but investigations continue, Chief Darryl Coleman of the Harris County Sheriff's Office said.
Texas Governor Greg Abbott told the media he could not confirm storm-related deaths.
The National Weather Service (NWS) says conditions are "unprecedented".
It said there was a "flash flood emergency" across the Houston Metro area, with travel near impossible.
Many shelters have been opened, including in a convention centre.
Governor Abbott said about 250 roads and motorways had been closed in Texas and that he had made a federal disaster declaration for 19 counties that was granted by President Donald Trump.
"We are dealing with a triangle of ongoing rain, including Houston, Victoria and Corpus Christi cities," Mr Abbott said.
"We will continue receiving incredibly heavy rain."
The NWS earlier noted reports of five deaths in the area, but only one fatality in Houston has been confirmed.
Two deaths have so far been confirmed from the storm since it made landfall:
- In Aransas County, where Rockport is the chief town, a person died in a house fire on Friday night
- A woman died in Houston as she drove through flooded streets on Saturday
Houston Mayor Sylvester Turner has urged residents not to call emergency services unless their situation is life-threatening and they need to be rescued.