A tornado raging through a city on the US-Mexico border has killed 13 people and ripped an infant from its mother's arms.

The tornado swept through the northern Mexican city of Ciudad Acuna, flipping over cars and tearing down homes.

The 13 dead included three babies, while hundreds of people were injured.

In Texas, 12 people were reported missing in flash flooding.

The baby was also missing after the twister tore the child's carrier from her mother's hands and sent it flying, said Victor Zamora, interior secretary of the state of Coahuila.

In Ciudad Acuna, at least 300 people are being treated at local hospitals, and up to 200 homes had been completely destroyed, officials said.

"There's nothing standing, not walls, not roofs," said Edgar Gonzalez, a spokesman for the city government.

Rescue workers dug through the rubble of damaged homes in a race to find victims. The twister hit a seven-block area, which Mr Zamora described as "devastated".

Photos from the scene showed cars with their hoods torn off, resting upended against single-storey houses. One car's frame was bent around the gate of a house.

A bus was seen flipped and crumpled on a road.

Mexican President Enrique Pena Nieto said he planned to travel to Acuna later with officials from government agencies.

A spokesman for the National Meteorological Service said it was the strongest tornado for at least 15 years in Mexico.

Ciudad Acuna, a city of 125,000, is just across the Rio Grande from Del Rio, Texas, where an estimated 750 homes were damaged.