At least nine people were killed when severe storms and a tornado struck an eastern area of the border between the US and Mexico, officials say.
On the US side, a tornado tore through a rural community in Texas, killing six people and injuring dozens more.
Just across the border, three people died in the city of Piedras Negras, where winds destroyed houses and cars.
Rescue workers and troops were carrying out door-to-door checks in the area, US officials said.
The tornado hit near the town of Eagle Pass, about 145 miles (230km) south-west of San Antonio.
Seventy-four people required hospital treatment, Mayor Chad Foster said, and the storm destroyed a primary school, around 20 houses and a local sewage plant.
On the Mexican side of the border, at least 40 people were injured and power lines had been toppled, a local official said.