According to Fox News and regional paper Colombia Reports, the attack took place on Tuesday between Codazzi and San Diego in the northern province of Cesar.
While no specific group has been named as the responsible parties in the incident – local media have only referred to them as an “armed group” – El Espectador reported on Tuesday that authorities might be looking at the guerrilla group FARC’s (Revolutionary Armed Forces of Colombia) 41st Front.
Reports put the number of injured at between four and six. Fox News reported late on Tuesday that three passengers aboard the first of the buses suffered bullet wounds and another three aboard the second vehicle received injuries when the bus went off the road.
The buses were reportedly two of several on the same road, though the drivers of the others were alerted prior to reaching the site.
Drummond officials did not release public comment on the incident.
Alabama-based Drummond Coal has operations in the US and Colombia. Its South American holdings are exclusively surface mines and export primarily to the US and Europe.