Drenching rains along the Texas-Mexico border trapped hundreds of people in flooded homes and in cars stranded in high waters, scrambling rescue crews to calls for help that continued Friday even as the downpours let up.

At least three people died in southern Texas and one across the border in Mexico after as much as 20 inches of rain fell in parts of the Rio Grande Valley, stranding motorists and causing widespread destruction.

U.S. Customs and Border Protection officers are increasingly searching electronic devices of travelers entering the country.