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A powerful chain-reaction explosion ripped through Mexico’s best-known fireworks market on the northern outskirts of the capital Tuesday, killing at least 26 people, injuring scores more and sending a huge plume of charcoal-gray smoke billowing into the sky.

The blast leveled the open-air San Pablito Market in Tultepec in the middle of the afternoon as it bustled with shoppers stocking up on fireworks to celebrate Christmas and New Year’s, reducing vendors’ stands to piles of rubble, ash, and charred metal. It was the third devastating explosion and fire to ravage the market since 2005.

Crescencia Francisco Garcia said she was in the middle of the grid of stalls along with a few hundred others when the thunderous explosions began. She froze, reflexively looked up at the sky and then took off running through the smoke once she realized everyone was doing so. As she ran she saw people with burns and cuts, and lots of blood.

“Everything was catching fire. Everything was exploding,” Francisco said. “The stones were flying, pieces of brick, everything was flying.”

Alejandro Gomez, chief prosecutor of the state of Mexico, raised the death toll from nine to 26 in comments broadcast on Mexican television. At least 70 injuries were reported. Authorities have not yet said what caused the explosion.

“Mexico is in mourning,” Mexico State Gov. Eruviel Avila said in an interview with Foro TV.

Sirens wailed and a heavy scent of gunpowder lingered in the air well after the explosion at the market, where most of the stalls were destroyed. The smoking, burned out shells of vehicles ringed the perimeter, and first responders and local residents wearing blue masks over their mouths combed through the ash and debris. Firefighters hosed down still-smoldering hotspots.

Cesar Ornelas of Atizapan de Zaragoza was only 10 minutes into shopping with his son and his father when he heard the first explosions. He tried to run, but something knocked him to the ground from behind. He tried several times to get up, unsuccessfully, and ultimately his 15-year-old son Francisco had to drag him out.

“We didn’t look back,” said Ornelas, who suffered light burns and a large bruise over his left kidney. His white tank top had a fist-size burn on the chest. “We heard how the explosion was kind of going off bit by bit.”

Nearly four hours later, he and Francisco limped gingerly out of the market area. Francisco said paramedics told him his leg was likely fractured by flying debris. Ornelas said his 67-year-old father, Ernesto, had run in a different direction and sought refuge in a nearby home. All the father’s clothing was burned, and his face and arm were bloodied. An ambulance had spirited him to a hospital, but Ornelas wasn’t sure where it was or how serious his injuries were.

The Mexican Red Cross said it sent 10 ambulances with 50 paramedics to the scene.

“My condolences to the families of those who lost their lives in this accident and my wishes for a quick recovery for the injured,” President Enrique Pena Nieto said via Twitter.

National Civil Protection Coordinator Luis Felipe Puente told Milenio television that some nearby homes were also damaged. The scene remained dangerous and he asked people not to come within 3 miles (5 kilometers) to avoid hampering the emergency response.

A similar fire engulfed the San Pablito Market in 2005, touching off a chain of explosions that leveled hundreds of stalls just ahead of Mexico’s Independence Day. A year later a similar incident at the same market also destroyed hundreds of stands.

Many in Mexico traditionally celebrate Christmas, New Year’s and other holidays by setting off noisy firecrackers and rockets.

(AP)