NEW : 25 people were killed and more than 100 are injured , interior ministry says . The explosion collapsed two floors of an office building , paramedics say . Rescuers have pulled a helicopter from the rubble , Mexico 's president says . Crews are searching for people trapped in the building .
NEW : 25 people were killed and more than 100 are injured , interior minister says . The explosion collapsed two floors of an office building , paramedics say . Rescuers have pulled a survivor from the rubble , Mexico 's president says . Crews are searching for people trapped in the building .