Mr. Trump said his administration was working with state and local officials and that Department of Homeland Security Secretary Kristi Noem would be arriving in Texas shortly. DHS oversees the Federal Emergency Management Agency.

The National Weather Service extended a flood watch July 7 through 7 p.m. local time for much of central Texas.

At least 81 people, including more than two dozen children, died in the torrential downpour. Dozens more were still missing three days later.