A massive explosion at a fireworks market near Mexico City killed at least 31 people and injured scores of others on Tuesday.

The blast occurred at the San Pablito marketplace ― about 20 miles outside Mexico City in the town of Tultepec ― where people were buying fireworks for Christmas celebrations.

The cause of the incident is still unclear, and Mexican authorities have opened an investigation into the blast. It is the third time a large explosion has hit the market in a little over 10 years, according to Reuters.

The blast tore through hundreds of stalls and left wreckage strewn across the area. Images of the aftermath show people attempting to help victims and putting out subsequent fires caused by the explosion.

JOSE LUIS TOLENTINO/Getty Images A massive explosion guts Mexico's biggest fireworks market near Mexico City on Dec. 20. The explosion killed at least 31 people and injured 72, authorities said.

JOSUE SOLANO/Getty Images An overhead view of the fireworks market after the blast.

RONALDO SCHEMIDT/Getty Images Firefighters work amid the debris left by the explosion.

RONALDO SCHEMIDT/Getty Images People search amid the debris.

Edgard Garrido/Reuters A man uses a water hose after the explosion.

AFP via Getty Images Part of the extensive damage caused by the blast.

RONALDO SCHEMIDT/Getty Images Soldiers and rescuers search amid the ruins.

Edgard Garrido/Reuters People look at a burned car afterward.

Edgard Garrido/Reuters An investigator takes photographs while walking among the wreckage of houses destroyed.

RONALDO SCHEMIDT/Getty Images People douse the embers amid the debris.

Edgard Garrido/Reuters A woman walks among the remains of houses.

Edgard Garrido/Reuters A soldier stands guard near the wreckage.