text: The blast in a town in Puebla state was apparently caused by thieves attempting to steal fuel from the pipeline.
  Oil gushed through the streets and caught fire, destroying homes and cars and forcing hundreds of people to flee.
  Mexican President Felipe Calderon has visited the scene and promised to launch an investigation.
  Puebla State Secretary Valentin Meneses said the explosion injured 52 people as well as destroying 32 houses and damaging scores more in San Martin Texmelucan - a small community about 80km (50 miles) east of Mexico City.
  He said that according to early indications, a criminal gang had punctured the pipeline.
  "They lost control because of the high pressure with which the fuel exits the pipeline. The streets began to flood, then came a spark and we saw rivers of fire in the streets," he said.
  In pictures: Mexico pipeline blast
  One local resident said she awoke at about 0530 local time to a strange, overpowering smell, like petrol.
  Minutes later, her street looked as if it was flowing in tar, and then it erupted in flames. Her husband knocked down a wall, allowing them to escape from the back of their home.
  "It was like we were living in an inferno. Everything was covered in smoke," she said, quoted by AP news agency.
  The fire was brought under control by midday, and the state oil monopoly Pemex said it had shut the pipeline down.
  President Calderon arrived in the town later on Sunday to survey the damage and visit the injured.
  He offered his condolences to the victims' families and said those responsible for the incident would be brought to justice.
  Pemex says that theft of oil from its pipelines is a chronic problem, costing it hundreds of millions of dollars a year.
target: At least 28 people have been killed and many others injured in an oil pipeline explosion in central Mexico, officials say.