Cold snap chills northern Mexico
Freezing weather and snow have paralysed much of northern Mexico, which is experiencing its lowest temperatures in more than 50 years.
Thousands of homes have been left without electricity and water, and schools and factories have been closed.
At least six people are reported to have died from the cold.
Among the worst-hit cities has been Ciudad Juarez, which is already suffering the worst violence in Mexico's drugs war.
Temperatures in the border city have dropped as low as -18C (0F).
"There have been cold temperatures in the past, but nothing that has lasted for so many days. It's been 40 years since the city has seen an emergency like this," city's civil protection chief Efren Matamoros told Reuters news agency.
The cold weather has shut down units at 17 power stations across northern Mexico, the Federal Electricity Commission said.
Factories have been asked to reduce their consumption of power, and there have been blackouts in some areas.
Mexico has also withdrawn an offer to temporarily supply electricity to Texas, where power stations have been hit by similar problems.
A huge swathe of the US and Canada has also been hit by a massive winter storm.