Rescuers toiled to wrest a young girl from the rubble of a partially collapsed school in Mexico City on Wednesday, offering a small glimmer of hope more than a day after a devastating earthquake killed at least 224 people.

Television stations broadcast the nailbiting, hours-long rescue attempt live after crews at the school in the south of the city reported seeing the girl move her hand. They threaded a hose through debris to get her water.

The girl's name was not made public, but her family waited in anguish nearby.

Rescuers moved slowly, erecting makeshift wooden scaffolding to prevent rubble from crumbling further and seeking a path to the child through the unstable ruins. They implored bystanders to be quiet to better hear calls for help.

It was part of the careful search for dozens of victims feared buried beneath the Enrique Rebsamen school, where officials reported 21 children and 4 adults dead after Tuesday's quake. Hundreds of buildings were destroyed by the country's deadliest earthquake in a generation.

"We have a lot of hope that some will still be rescued," said David Porras, one of scores of volunteers helping the search at the school, for children aged 3 to 14.

"But we're slow, like turtles," he said.

The magnitude 7.1 quake, which killed at least 93 people in the capital, struck 32 years to the day after a 1985 earthquake that killed thousands. Mexico is also still reeling from a powerful tremor that killed nearly 100 people in the south of the country less than two weeks ago.

Emergency crews, volunteers and bystanders toiled on Wednesday using dogs, cameras, motion detectors and heat-seeking equipment to detect victims who may still be alive more than 24-hours after the quake.
Reinforcements also began to arrive from countries including Panama, Israel and Chile, local media reported.

Hundreds of neighbours and emergency workers pulled rubble from the ruins of the school with their bare hands under the glare of floodlights a full day after the shock. Three survivors were found at around midnight as volunteer rescue teams known as "moles" crawled deep under the rubble.

By Wednesday morning, the workers said a teacher and two students had sent text messages from within the rubble. Parents clung to hope that their children were alive.

RESCUED KIDS

Overnight, volunteers with bullhorns shouted the names of rescued kids so that waiting family members could be reunited with them.

"The priority continues to be rescuing people from collapsed buildings and taking care of the injured," said President Enrique Pena Nieto. "Every minute counts."

Pena Nieto has declared three days of mourning.

The president has been unusually visible since the two earthquakes, a sign of the political sensitivity of disaster relief less than a year before the next presidential election.

The government’s widely panned response to the 1985 quake caused upheaval in Mexico, which some credited with weakening the 71-year rule of the Institutional Revolutionary Party (PRI). Pena Nieto, the PRI's first president since it lost power in 2000, hopes to elect a party successor next year.

On Wednesday, the president travelled to the state of Morelos, just south of the capital, where 71 people died, to survey damage. In Puebla state, site of the earthquake's epicentre, at least 43 died.

The earthquake toppled dozens of buildings, tore gas mains and sparked fires across the city and other towns in central Mexico. Falling rubble and billboards crushed cars and nearly 5 million homes, businesses and other facilities were without power at one point.

Although authorities and property owners will need time to fully assess the damage, initial reports suggest that collapses were limited mostly to buildings that predate the 1985 quake, after which stricter building codes were enacted.

But even wealthier parts of the capital, including the central Condesa and Roma neighbourhoods, were badly damaged as older buildings buckled. Because bedrock is uneven in a city built on a drained lake bed, some districts weather quakes better than others.

"The central part of Mexico City, in the lake bed, is always going to be a complicated place to build," said Rodrigo Suarez, chief operating officer at Mexico City-based apartment developer Hasta Capital. "These old buildings (may) survive an earthquake or two or three, but since they weren't built to modern code, there's always going to be a risk in major earthquakes.”

In Puebla, where the U.S. Geological Survey said the epicentre lay some 100 miles (158 km) southwest of the capital, parts of colonial-era churches crumbled. In the town of Atzala, a row of coffins lined the street outside a church where the roof collapsed, killing 11 worshipers inside.

VOLCANO ERUPTS TOO

Around the same time that the earth shook, Mexico's Popocatepetl volcano, visible from the capital on a clear day, had a small eruption. On its slopes, a church in Atzitzihuacan collapsed during Mass, killing 15 people.

In Rome, Pope Francis said he was praying for Mexico, a majority Catholic country. "In this moment of pain, I want to express my closeness and prayers to all the beloved Mexican people," he said.

U.S. President Donald Trump said in a tweet on Tuesday: "God bless the people of Mexico City. We are with you and will be there for you." Trump and Pena Nieto spoke at length on Wednesday, according to the White House.

Some volunteers in the capital, home to some 20 million people, expressed frustration at the disorganization among military and civilian emergency services, which competed over who would lead the rescue efforts.

Javier Gonzalez, a 21-year-old civil engineering student, spent the night along with two classmates helping at one of the collapsed buildings in the Roma neighbourhood, then moved on to the Enrique Rebsamen school early Wednesday where they saw officials bickering over the rescue effort.

"The firefighters and emergency services personnel were more worried about who was in charge," said Gonzalez.