MEXICO CITY - Ten cities in Mexico registered record-high temperatures in 10 cities, including the capital, authorities said on Friday, amid a searing heat wave that has prompted blackouts nationwide and pushed the power grid to the brink.

In the normally temperate high-altitude capital of Mexico City, North America's largest metropolis, thermometers on Thursday peaked at 34.3 degrees Celsius (93.7 degrees Fahrenheit), a tenth of a degree higher than the record hit just a month earlier.

Neighboring Puebla broke its previous record of 34.3 C - set in 1947 - when it reached 35.2 C on Thursday.

In Ciudad Victoria, in the northern border state Tamaulipas, across from Texas in the United States, the temperature hit a sweltering 47.4 C on Thursday, breaking the previous high set in 1998.

The intense heat caused blackouts lasting several hours in some areas of Mexico this week, mainly in the north, and caused classes to be suspended in the central state of San Luis Potosi, which this week reached 50 C.

In a weekly report published on Thursday, Mexico's health ministry reported seven heat-related deaths this heat season between its start on March 17 and May 4, a tally that could rise after this week's brutal heat.

Human-caused climate change and El Nino have been pushing up temperatures worldwide and causing deadly heat waves.

Mexico's electricity system regulator issued several alerts this week as demand in some parts of the country exceeded supply.

Business chambers and sector analysts criticized the blackouts, accusing the government of not investing in energy transmission networks or in sufficient generation to cover demand.

President Andres Manuel Lopez Obrador, who leaves office in October, described the blackouts as "exceptional" and assured that Mexico has sufficient generation capacity.

The heat wave comes amid a severe nationwide drought that has caused a worsening water crisis in much of Mexico, making water a key issue in June general elections.

  - Reuters