Emergency responders worked into the morning Wednesday to recover any remaining victims and assess damage from the tornado that hit a few miles south of Eagle Pass in an unincorporated area of Maverick County, about 150 miles south of San Antonio.
The tornado caused the only reported fatalities Tuesday in Texas as severe thunderstorms brought high winds, flooding rains and hail to parts of the state.
Eagle Pass Mayor Chad Foster said four of the six fatal victims were apparently in one mobile home when the tornado hit Tuesday night. A local hospital received 74 injured patients. Four patients in critical condition were transported to regional hospitals, he said.
"The hospital in the early stages was being overrun, but they had called in additional doctors and were able to take care of business," Foster said.
Hospital officials could not immediately be reached by phone.
Mexican authorities reported at least three more deaths across the border, in the town of Piedras Negras.
The storm left at least 40 people injured and knocked out power in Piedras Negras, across from Eagle Pass, said Oscar Murillo, the Mexican city's civil protection director.
Hail pelted the city for about 15 minutes, damaging roofs of houses, toppling power poles and damaging dozens of cars. A church in one neighborhood was destroyed.
Back in the U.S., the tornado destroyed Rosita Valley Elementary School, more than 20 nearby homes and the Eagle Pass municipal sewer treatment plant. Nobody was in the school when the tornado hit, Foster said.
"I'm out here on site and I'm looking at what used to be an elementary school," Foster said by cell phone in the early hours of Wednesday morning. "Six mobile homes are still missing."
The Eagle Pass school district canceled classes for Wednesday, Foster said.
The National Weather Service confirmed that a tornado struck a few miles south of Eagle Pass just after 7 p.m.
The thunderstorm that produced the deadly tornado developed over Mexico and moved southeast over the Rio Grande and across Maverick County, said Clay Anderson, a senior forecaster with the Austin-San Antonio office of the weather service.
In North Texas, streets flooded and roofs peeled off homes as storms began moving through Tuesday afternoon, followed by another line of severe storms about six hours later. Tornado sirens rang in several counties, and television footage showed drivers and residents being rescued from flooded cars and suburban neighborhoods.
In Denton County, heavy winds blew the metal roof off a restaurant and damaged several mobile homes and a commercial building under construction, said Roland Asebedo, assistant chief for Denton County's Emergency Services. No injuries were reported, he said.
American Airlines had about 200 flights canceled because of weather in Dallas, spokesman Billy Sanez said. The airline also diverted about 80 flights bound for Dallas-Fort Worth International Airport to other airports, including San Antonio.
Sanez said American was working with the San Antonio airport and the Red Cross to house passengers at a nearby high school because hotel rooms were scarce. American also gave Dallas-bound passengers the option of continuing by bus.
Ken Capps, vice president of public affairs at DFW airport, said the airport's flight control tower was temporarily evacuated Tuesday night but the airport remained open. Weather canceled 160 of about 950 departing flights Tuesday, and cots were provided for stranded passengers, airport officials said.
About 4,000 customers in North Texas remained without electricity late Tuesday after about four times that many lost power earlier in the day, said Gailee Cardwell, a spokeswoman for Oncor Electric Delivery, a newly named subsidiary of TXU Corp.