MEXICO CITY , Mexico ( CNN ) -- A truck carrying more than 25 tons of dynamite exploded Monday in northern Mexico , killing at least 23 people and injuring more than 140 , a government spokesman said . Of the 140 injured , 30 suffered critical wounds and five were listed in extremely critical condition , said David Aguisn , spokesman for Humberto Moreira , the governor of the state of Coahuila . Notimex , Mexico 's official news agency , reported at least 30 people were killed in the blast at a factory near Monclova -- about 125 miles ( 200 kilometers ) northwest of Monterrey . Three Mexican reporters were among those killed , according to Notimex . Video footage showed the burned-out , mangled shell of the truck and nearby cars damaged by the blast . Aguisn said that there is no indication of foul play . The cause of the explosion is under investigation . E-mail to a friend . CNN 's Ariel Crespo contributed to this report .
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 .