Two people were killed and four others injured when a truck carrying ammonium nitrate collided with another vehicle and exploded on a national highway in northern China at around noon on Sunday, state news agency Xinhua reported. Authorities in Inner Mongolia autonomous region said the blast occurred at 11.27am on a section of National Highway 331 in Xilingol League, according to the report. Officials said a truck carrying hazardous chemicals collided with another transport vehicle, leaving two.