Published: Feb 01, 2013 5:20 AM EST

MEXICO CITY (AP) - Rescuers in Mexico City are using rescue dogs, trucks and a crane to search for victims in the rubble of three floors of one of the city's tallest buildings.
    
An explosion Thursday afternoon next to the state-owned oil company, Pemex, killed at least 25 people and injured more than 100.
    
Officials say the first two floors and basement of the 51-story tower collapsed. Many office workers were outside having lunch at the time of the blast.