Mexico worked Wednesday to identify the charred bodies of dozens of people killed in an explosion at its biggest fireworks market, as authorities investigated what caused the multi-colored salvo of destruction.
Thirty one people are known to have died in the Tuesday blast -- 26 at the scene and five more in hospital. Forensic experts are working on genetic analyses of the bodies because nearly all are impossible to identify.
Rescue workers were still searching for bodies -- or survivors -- in the smoldering wreckage of the market in the Mexico City suburb of Tultepec, which was packed with customers buying pyrotechnics for traditional end-of-year festivities.
Another 72 people were injured in the blast. Fifty-one remained in hospital on Tuesday night, many with severe burns covering their bodies. Another 21 people with lesser injuries were treated and released.
Three badly burned children were due to be transferred to a specialist hospital in Galveston, Texas.
Residents were left traumatized by the cataclysmic scene.
"You just heard the blast. And everything started to catch fire. People came running out on fire," said Walter Garduno.
"People were alight -- children," he added before trailing off.
From a few kilometers (miles) away, the multiple explosions almost looked festive, alight in blue, red and white. They were anything but.
The scorched remains of the San Pablito market looked like something from a post-apocalyptic film, with little left standing in the smoldering ruins.
The explosion sent a vast cloud of smoke billowing over the capital. An acrid smell hung in the air well into the night.
Fire crews struggled for three hours before bringing the blaze under control.
The head of the civil protection service, Luis Felipe Puente, said crews had to wait for all the fireworks to finish exploding before they could extinguish the flames.
"The entire market is gone," he said. It had more than 300 stands.
Several of the injured were in "delicate condition," he added.
Small explosions continued to startle locals through the night. Authorities said they were controlled blasts to eliminate remaining gunpowder.
Homes and vehicles nearby were also severely damaged. In some areas, emergency workers were gently probing for survivors under heaps of charred and twisted roofing material.
People desperately searching for family and friends shouted and gestured to rescuers about where they hoped the missing might be found.
The military, which is in charge of issuing fireworks sales permits, was deployed to help emergency crews transport casualties to hospitals by ambulance and helicopter.
Ambulances, fire trucks, police vehicles and army trucks all crowded the sprawling blast area.
Six initial explosions
Mexico's President Enrique Pena Nieto tweeted his condolences to the families of those killed.
The attorney general's office has opened an investigation into the cause of the blast, which it said was prompted by six initial explosions.
State and federal investigators were combing through the burnt remains of the market.
That was the cause of an explosion at the same market in September 2005 ahead of the Independence Day holiday.
The following year, another explosion destroyed more than 200 sellers' stands. Both incidents left dozens of injured, but no fatalities.