Mexico oil company Pemex blast: Death toll rises to 25 MEXICO CITY An explosion at the office headquarters of Mexico's state-owned oil company killed 25 people and injured 101 on Thursday as it heavily damaged three floors of a building, sending hundreds into the streets and a large plume of smoke over Mexico City's skyline. Rescuers continued to search the rubble for victims trapped in the debris late Thursday with the aid of rescue dogs, trucks with mounted lights and an oil company crane. Interior Minister Miguel Osorio Chong said it was uncertain if there were any people still trapped but that crews would keep searching. Many of the office workers were outside having lunch when the explosion occurred about 3:45 p.m. local time in a basement parking garage next to the iconic, 51-story tower of Petroleos Mexicanos, or Pemex, one of the tallest buildings in Mexico City. Osorio Chong said the explosion hit the basement and first two floors, which rescuers said had collapsed. President Enrique Pena Nieto said authorities have not yet found what caused the blast in the 14-story building in a busy commercial and residential area. The company later tweeted that the Attorney General's Office was investigating the explosion and any reports of a cause were speculation. Ana Vargas Palacio was distraught as she searched for her missing husband, Daniel Garcia Garcia, 36, who works in the building. Hundreds of firefighters, military in camouflage and Red Cross workers hauled large chunks of concrete and looked for victims late into the night, with at least four bodies pulled out of the rubble, according to an Associated Press reporter at the scene. The exploded building was intact on the outside but filled inside with debris. Television images showed people being evacuated in office chairs, and on gurneys. "We were talking and all of sudden we heard an explosion with white smoke and glass falling from the windows," said Maria Concepcion Andrade, 42, who lives on the same block as the Pemex building. Police landed four rescue helicopters to remove the dead and injured. My condolences to their families," Pena Nieto said via Twitter. He later toured the scene. The injured were taken to Pemex's hospital in the capital's northwest delegation of Azcapotzalco and the Red Cross hospital in the Polanco neighborhood near the oil company's office headquarters, where relatives huddled in the waiting room for news of their loved ones. Pemex, created as a state-owned company in 1938, has nearly 150,000 employees and in 2011 produced about 2.5 million barrels of crude oil a day, according to its website, with $111 billion in sales.