It was carrying more than 25 tons of dynamite . At least 30 people injured in the incident , government spokesman says . No foul play suspected , spokesman says ; cause under investigation . Mexican news agency reports higher death toll of 31 .
Truck was carrying more than 25 tons of dynamite . At least 140 people injured in the blast , government spokesman says . No foul play suspected , spokesman says ; cause under investigation . Mexican news agency reports higher death toll of 30 .