Brazil’s Federal Police discovered a cache of military-grade weapons buried on the outskirts of an indigenous Amazon village on the border with Peru and Colombia, and arrested two Colombians on suspicion of arms trafficking.

The weapons were located in a field in a Ticuna village near Tabatinga, Amazonas state. Police, reportedly acting on an anonymous tip, seized grenades, a submachine gun, grenade launcher, rifles and ammunition. One rifle was identified as belonging to Peru’s Armed Forces.

Federal Police arrested two Colombian nationals, who said they belonged to the Ticuna, an indigenous group native to the border region. The men face multiple weapons charges and the police are investigating the possibility of a larger trafficking network in the area. The detained men reportedly admitted to guarding the arsenal as employees of Peruvian drug kingpin Jair Ardela Michue, alias “Javier,” who was arrested in March 2011.

The Brazilian government has increased enforcement efforts in Amazonas State since implementing their Strategic Border Plan and have been working in cooperation with Colombia to combat narco-trafficking in the region.