The freight platform of a Mexican flatbed truck carrying 40 political activists apparently loosened, fell off and struck another vehicle last weekend along a remote highway in the southern state of Chiapas. The 17-year-old driver of the truck may have been driving while intoxicated, according to published reports.

The truck was carrying supporters of a leftist party when it crashed into a pickup, killing 10 people and injuring 18, the Arizona Republic reported. The accident occurred on a mountain road about 60 miles southeast of Tuxtla Gutierrez.

Supporters of the Democratic Revolution Party were returning from a campaign rally about 25 miles away when the accident occurred. Several of those injured were reportedly in critical condition.