"The vehicle was heading toward [the Mexican town of] Jocotepec when the braking system apparently malfunctioned, resulting in the driver trying to stop the vehicle and crashing into a wall on a roadside head-on. There are 20 people injured... So far, 14 people have died," the secretariat said on Twitter.
The bus was transporting workers of a berry production company in coordination with the local authorities. The bus driver has died.
Emergency services are continuing rescue operations at the scene.