Blast rocks headquarters of Mexico oil giant

Aljazeera At least fourteen people have been killed and some 80 others injured after an explosion rocked the skyscraper that houses the headquarters of Mexican oil giant Pemex in Mexico City. "What took place was an explosion in the B2 building of the administrative centre. There are injuries and damage on the ground floor and mezzanine," the state-owned company said on Thursday. Al Jazeera's Adam Raney, reporting from Mexico City, said that the interior minister had confirmed the casualties, but there were still people missing. "There are people trapped under rubble still - we have seen a massive rescue operation launched here by firefighters and rescue workers," our correspondent said. The blast was caused by "an accumulation of gas" in an electricity supply room of the building's lower floors, a spokesperson for the city's civil protection agency said. Heavy damage Television images showed heavy damage on the tower's ground floor and people being carted away on stretchers and office chairs. Police have cordoned off the  streets around the building [AFP] Mayor Miguel Angel Mancera, who headed to the scene of the accident, said rescue and public safety personnel were at the scene. Pemex, the world's fourth-largest producer of crude with around 2.5 million barrels per day, announced earlier that it had evacuated the building due to a power failure. The company has experienced deadly accidents at its oil and gas facilities in the past. Last year, a huge explosion killed 30 people at a gas plant near the northern city of Reynosa, close to the US border. The previous worst incident took place in December 2010, when an oil pipeline exploded after it was punctured by thieves in the central town of San Martin Texmelucan, leaving 29 dead and injuring more than 50. In October 2007, 21 Pemex workers died during a gas leak on an oil platform in the Gulf of Mexico. Most drowned when they jumped into the sea in panic.