At least 27 people were killed and 52 injured after an oil pipeline exploded Sunday morning in central Mexico, the state-run news agency said. The cause of the explosion in San Martin Texmelucan, in Puebla state, was under investigation, but preliminary reports pointed to the illegal extraction of oil from the pipe, said Laura Gurza, coordinator for civil protection in Puebla. The situation was under control, but the extent of the damage was still being assessed, Civil Protection Director Miguel Angel Martinez said. The pipe belongs to Pemex, the state-owned oil monopoly. Some 32 houses were lost in the blast, and 80 others were partially damaged, Martinez was quoted as saying by CNN.