MEXICO CITY - Mexico waited with bated breath on Thursday for signs of life in the rubble of a collapsed school as a desperate search for survivors of a devastating earthquake entered a third day.

The country’s civil protection organization put the death toll following Tuesday’s 7.1 magnitude quake at 233 people, but that toll was expected to rise.

As rescue workers scrabbled to remove tons of rubble at dozens of collapsed buildings in the capital and across several central states, most of the country’s attention focused on a school in the south of Mexico City.

There, somewhere in the mountain of debris that was once a wing of the Enrique Rebsamen school, at least one little girl was still alive, officials said.

“We know that there is a child alive inside. What we do not know is how to reach her... without risking a collapse and putting rescuers in danger,” rescue coordinator Jose Luis Vergara told Televisa about a young girl whose fate is being closely followed by the country.

A slightly-built civilian volunteer was able to squeeze into a narrow passage through the rubble to pass oxygen and water through a tube.

The military said the girl had spoken, managing to say “I’m very tired.”

Many children are still missing at the school where 21 children - aged between seven and 13 - and five adults were crushed to death.

In the first hours after the quake, 11 children and at least one teacher were rescued.

But time is running out. Experts say the average survival time in such conditions and depending on injuries is 72 hours.

“The armed forces have made the decision... to continue the search until, hopefully, it ends in success,” Education Minister Aurelio Nuno said.

The body of a 58-year-old woman was pulled from the rubble overnight.

The Civil Protection organization put the overall death toll at 233 - 102 in Mexico City, 69 in Morelos state, 43 in Puebla, 13 in Mexico state, five in Guerrero and one in Oaxaca.

In Puebla, a picturesque colonial city near the quake’s epicenter, several churches were damaged and one collapsed, killing 11 people attending a baptism, officials said.

Residents of San Gregorio in Xochimilco barrio in Mexico City’s far south were angry at the lack of material aid and volunteers.

“I need volunteers! Yesterday everything arrived and now there is nobody. They come, they do some disaster tourism, and they leave,” one volunteer who gave his name as Morales told AFP.

San Gregoria was badly hit by the quake with many collapsed buildings and others in a state of near-collapse.

There were stories of hope emerging in ruined buildings across the city, where more than 10,000 people lost their lives in a devastating earthquake in 1985.

In the north, a man who had been trapped for 26 hours and a 90-year-old woman were taken alive from the rubble.

Rescue teams were helped by thousands of ordinary civilians who dug through the rubble alongside them. Other Mexicans took to the streets with food and water for victims and emergency workers.

President Enrique Pena Nieto toured the hardest-hit areas and declared three days of national mourning.

“The priority remains saving lives,” he said in a broadcast to a grieving nation, insisting there was still hope of finding survivors.

More than 50 people have been rescued from collapsed buildings in the capital, he said.

US President Donald Trump called Pena Nieto and offered assistance and search-and-rescue teams which were quickly being deployed, the White House said.

Rescue teams have flown in from Israel, El Salvador and Panama and more were expected from Ecuador, Honduras, Colombia and Spain.

The earthquake hit on the anniversary of a huge quake in 1985 that killed more than 10,000 people, the disaster-prone country’s deadliest ever.

Tuesday’s temblor struck just two hours after Mexico held a national earthquake drill, as it does every September 19 to remember the 1985 disaster.

A system of quake sensors was set up in 1993 along the Pacific coast, where tremors are more common.

People in Mexico City were not warned by it on Tuesday because the epicenter was only 120 kilometers (75 miles) outside the capital and thus outside the main area of sensor coverage, said Carlos Valdes of the National Center for Disaster Prevention.

Adding to the national sense of vulnerability, the earthquake struck just 12 days after another quake that killed nearly 100 people in southern Mexico.