As the search for the last possible survivors of this week's powerful earthquake intensified Friday, the scale of damage across central Mexico became more evident.
At least 3,000 buildings in the densely packed capital have suffered damage from the devastating 7.1 quake, Mayor Miguel Angel Mancera said, with a number of structures declared uninhabitable.
Many others with cracked facades and crumbling balconies are still waiting for official inspections, leaving weary occupants uncertain whether to remain.
In the badly hit state of Morelos, where the epicenter of the quake was located, Gov. Graco Ramírez said 20,000 houses were damaged, along with186 schools.
Heavy rains have complicated search efforts this week, forcing some crews to retreat amid piles of sodden debris, and more rain was expected Friday night.
Authorities have not released an estimate for the number of people believe trapped or possibly dead inside damaged buildings. The most recent reports indicate that at least 293 people were killed in Tuesday's quake: 155 dead in Mexico City, 73 in Morelos state, 45 in Puebla state, 13 in Mexico state, six in Guerrero and one in Oaxaca.
As the window narrowed in which trapped victims might still be found alive, Mexican authorities assured residents that officials would not give up efforts to find anyone who may still be alive.
"The work of rescue … will not be suspended," Mexican President Enrique Peña Nieto said in a visit to Puebla state. "We will maintain the work of rescue to look for anyone who may be alive beneath the rubble."
Peña Nieto publicly rebuffed "false rumors" that rescue efforts soon would be suspended and heavy machinery deployed at damaged sites, a possibility that has inspired panic among relatives of the missing. He said nothing would be demolished until after a census of damaged buildings was complete.
"Throwing in the towel is not an option!" Secretary of the Navy Vidal Soberon declared in a tweet.
Authorities said rescue work was still being carried out in eight of the 38 collapsed buildings across the capital.
Rescue crews from around the world — including teams from the U.S., Israel and Japan — have descended on Mexico to help with relief efforts.
They have joined firefighters, soldiers, naval officers and a volunteer force of search and rescue specialists known as the Topos — the Spanish word for moles.
On Friday afternoon, the Topos combed through the rubble of a collapsed five-story apartment building in the Tlalpan district in southern Mexico City. Rescue teams were using dogs and heat and sound detectors to look for life.
"It's a very emotional moment when you hear a sound that indicates life," said Alejandro Castro, who commands a Cancun-based unit of volunteers. "At that moment, you of course hope they will survive, but it is impossible to know."
At least eight people have been rescued alive from the building, authorities say. But on Friday, Azteca TV reported that five of those brought out were dead.
Workers removed their hard hats in respect as colleagues maneuvered one body laid out on an orange stretcher down from the rubble pile on a ladder. From there, they loaded it into a waiting morgue trailer.
Across the city, hopes that the missing would be found alive were being dashed.
In a poignant scene widely aired on Mexican TV, Karina Gaona stood earlier this week in front of a downed building in the hard-hit Roma district and, in a loud voice, expressed support for her brother, Erick Gaona Garnica, who went missing in the structure.
"Brother, hang in there, please. We are going to get you out," she had declared. "Your daughter is well … your wife is well, your parents and brothers are well. You know that we love you, and we are not going to move from here until we get you out. God take care of you."
On Friday, news circulated that the brother's body had been pulled from the rubble of the building.
Food and supplies continued to pour into the damaged areas to help earthquake victims. Meanwhile, nearly 2 million Mexicans have signed a petition through Change.org asking that the National Electoral Institute, a public organization that organizes federal elections, donate about $7 million to the victims of Tuesday's earthquake and another deadly quake that hit southern Mexico a few weeks earlier.
"It is not fair to allocate so much of our tax money to political parties," the petition said, "if thousands of Mexicans are suffering from this enormous tragedy."
Special correspondent Cecilia Sanchez contributed.
3:40 p.m.: This story was updated with additional details on rescue efforts and tallies of structures damaged by the earthquake.