MEXICO CITY (January 31, 2013)—At least 14 people died and 80 more were injured Thursday in an office building explosion at the headquarters of Petroleos Mexicanos, or Pemex, in Mexico City, the country’s state-run oil company said.

An explosion at the main headquarters of Pemex also damaged three floors of the building, sending hundreds into the streets and a large plume of smoke over the skyline.

There was no immediate cause given for the explosion, which occurred in the basement of an administrative building next to the iconic, 52-story Pemex tower.