Ankoko Island (Isla de Anacoco in Venezuela) is located at the confluence of the Cuyuni River and Wenamu River, at 6°43′N 61°8′W / 6.717°N 61.133°W, on the border between Venezuela and the disputed area of Guayana Esequiba.
Venezuela, which claims Guayana Esequiba, as part of its territory established a military base in 1966 which Guyana claims as intrusion and aggression on a territory which sovereignty was never under discussion.
In February 1966, the governments of Venezuela, the United Kingdom and Guyana signed the Geneva Agreement aimed at resolving the controversy over the Venezuelan claim that the arbitral award of 1899, which settled the border between Venezuela and Guyana, was null and void.
The Agreement provided that "no new claim or enlargement of an existing claim to territorial sovereignty in these territories (of Venezuela and British Guiana) shall be asserted while this Agreement is in force, nor shall any claim whatsoever be asserted otherwise than in the Mixed Commission while that Commission is in being".
Despite this declaration, a few months later a well-armed group of Venezuelan soldiers, along with civilians, encroached upon and occupied territory by Guyana de facto side of the border. This encroachment occurred, unknowing to Guyana Government, on the half of the island of Ankoko that Guyana claims as its own at the confluence of the boundary rivers, Cuyuni and Wenamu (Wenamo). It took the form of the introduction of military and civilian personnel and the establishment of an airstrip and the erection of other installations and structures, including a post office, school and military and police outposts.