AlQa'dah 4, 1434, Sep 10, 2013, SPA -- At least 43 people died and 39 were injured when two buses collided on a highway connecting Tehran and Qom, UPI quoted police and medical officials as saying. Officials said the collision Monday was so forceful that a fire broke out and trapped some victims inside the burning buses, Iran's government-backed Tasnim News Agency reported Tuesday. One Iranian official said the crash's likeliest cause was defects in the vehicles' electrical systems.