NEW : 25 people were killed and more than 100 are injured , interior minister says . A large plume of smoke rose near the building after the explosion around 4 p.m. Thursday , and emergency crews swarmed the scene . The explosion collapsed two floors of an office building , paramedics say . Comment: 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 . Comment: Crews are searching for people trapped in the building .