Costa Rican authorities on Wednesday announced the discovery of a cache of 15 assault rifles and a rocket launcher in a mountainous area near the border with Nicaragua that also served as a clandestine heliport.

The find occurred on Monday during an operation by the Border Police near the town of Cutris, in Alajuela province, the Security Ministry said in a communique.

"The armaments were hidden in a mountainous sector where authorities went after inquiries and reports they received over several days about the movements of suspicious people and vehicles in the zone," the statement said.

The weapons, as well as dozens of rounds of ammunition, were found in an improvised camp where authorities also found 10 containers of fuel that they suspect were to be used to refuel a helicopter.

The weapons are new and in very good condition, and so authorities are ruling out that they are left over from the wars that wracked Central America in the 1980s, Security Minister Mario Zamora said.

Police on Wednesday conducted an operation to try and find at least five people who have been linked with the weapons.

They are also working to rule out the presence of landmines and any other type of explosives in the vicinity.

The authorities' primary hypothesis is that there is a group devoted to arms trafficking operating in the area, but they still do not know the origin or destination of the arsenal. EFE