Gangs in Haiti opened fire on an armored vehicle over the weekend, leaving four soldiers from El Salvador unaccounted for in the first major attack since an international gang suppression force began operations in the violence-wracked Caribbean country.

The attack occurred Sunday in Croix-des-Bouquets, a once peaceful community in Haiti's capital, Port-au-Prince, that is now controlled by violent gangs.

The armed forces of El Salvador said in a statement Monday that the four aviation technicians were returning to camp when the armored vehicle was attacked with explosives and set on fire.