AN explosion at a fireworks market outside Mexico City has killed 31 people and injured more than 70 others.
The blast ripped through the San Pablito fireworks market in Tultepec, about 32km outside the city.
Videos from the scene show a large number of fireworks going off into the air as they caught fire.
The Mexican Red Cross said it sent 10 ambulances with 50 paramedics to the market, where emergency services had to wait to attend victims until the majority of the fireworks had burnt out.
Locals have been told to keep at least five kilometres away from the market until authorities secure the blast zone.
Luis Felipe Puente, head of the national emergency services, said there was no choice but to let any unexploded fireworks burn off.
Some injured children suffered burns to more than 90 per cent of their bodies and have been sent to the US city of Galveston, Texas, for specialist treatment.
Eruviel Avila, governor of the State of Mexico, said most of those killed have such severe burns that they will need to be identified using DNA testing.
Reports say the market contained up to 300 tonnes of fireworks, and the explosions had also damaged nearby buildings.
This was not the first time an explosion has occurred, fireworks caught fire and exploded in 2005 and again a year later.