Frantic search for children trapped in Mexican school after earthquake as rescuers make contact using WhatsApp

Hopes of finding more alive had been raised by a WhatsApp message sent from one trapped girl to her parents: six hours after the collapse, Fatima had used her remaining battery to text: “I am fine, I am trapped with four other kids, please help us, we are thirsty.”

They were reportedly pulled to safety on Tuesday night, among a dozen or more survivors. But as rescue efforts stretched on, there were growing fears for up to 30 still believed missing. 

The death toll across the disaster zone stood at 225 as rescuers continued to dig through buildings pulverized or crumpled like concertinas by the earthquake on Tuesday afternoon. 

Forty-three of the deaths were in the state of Puebla, some 75 miles east of Mexico City, where the earthquake had its epicentre, while 71 people were killed in Morelos, to the south of the capital. 

But it was Mexico City itself that was hardest hit, with 94 confirmed dead, according to Luis Felipe Puente, national coordinator of the Civil Protection service.

At least 44 buildings, many of them blocks of flats, were flattened by the quake, vast clouds of dust mushrooming across the city’s skyline as they fell. 

Some of the worst damage occurred in the fashionable neighborhoods of La Condesa and La Roma, home to historic architecture and many of the city’s expats.

On the La Roma avenue of Alvaro Obregon, rescuers and sniffer dogs were battling to reach 13 people trapped alive in one crumpled building after pulling out dozens of others.

Earlier, onlookers had erupted in cheers as a dog was rescued unharmed.

Much of the region was plunged into darkness, with 40 per cent of Mexico City and 60 per cent of the state of Morelos still without electricity yesterday morning, though the majority had seen services restored by last night.

Amid scenes of mayhem and a series of aftershocks, President Enrique Peña Nieto urged people to stay in their homes if it was safe to do so, and keep the streets clear to allow emergency vehicles to pass.

"This earthquake is a hard and very painful test for our country," he said in a message to the nation. "Us Mexicans have had difficult experiences as a consequence of earthquakes in the past. And we have learned to respond to these episodes with commitment and the spirit of solidarity."

Mr Peña Nieto later announced three days of mourning for the victims, adding: "Mexico shares their pain".

(The quake) struck just 11 days after an 8.1 magnitude earthquake - the most powerful to hit Mexico in decades - killed around 100 people in the southern states of Oaxaca and Chiapas.

It also came 32 years to the day since the devastating Mexico City quake of 1985, when at least 5,000 people died in the capital. 

But while Mexican citizens won praise for flooding to join rescue efforts, some criticised what they said was a slow and chaotic response by authorities.

Despite earthquake drills being held in Mexico City just hours earlier, volunteers at the site of collapsed buildings were nevertheless forced to put out appeals on social media for basic equipment.

Miguel Angel Osorio Chong, the interior secretary, was booed and pelted with objects by an angry crowd as he toured a site in the capital.

Dr Raul Valenzuela, investigator at the Institute of Geophysics at the National Autonomous University of Mexico (UNAM), said Mexico City had suffered such damage due to the proximity of the epicentre in neighbouring Puebla.

He said that the area had suffered such quakes before, but that this was unusually close and strong. Mexico City, especially its centre, had suffered badly due to its situation on the unstable lakebed which underpins the capital, Dr Valenzuela told Aristegui Notices. 

The Popocatépetl volcano erupted in the hours after the quake, a thick grey plume visible from Mexico City. 15 people were killed when a church on its slopes collapsed during mass, said the governor of Puebla, Jose Antonio Gali.

It remained on yellow alert on Wednesday.