(Bloomberg) – Venezuela’s acting President Delcy Rodríguez arrived at The Hague to represent her country before the International Court of Justice in a land dispute with Guyana over resource-rich territory. 

“It has become abundantly clear that the only party holding title to this territory” is Venezuela, Rodríguez told her nation’s state television upon arrival in the Netherlands. It’s her first trip outside the Caribbean since her predecessor, Nicolás Maduro, was captured at the start of the year by U.S. forces. 

The border controversy, a legacy of British colonialism on the eastern shoulder of South America, centers around the Essequibo, a western region of neighboring Guyana that Venezuela has long claimed as its own. The tribunal will consider the merits of Guyana’s case on the validity of an 1899 Arbitral Tribunal Award that settled the land boundary between Venezuela and what was then British Guiana.

ExxonMobil has made huge offshore oil discoveries over the past decade in a maritime swath that Caracas sees as an extension of its claim to the Essequibo. Over the years, the Venezuelan Navy has patrolled the waters in an apparent act of intimidation against research vessels operating on behalf of US oil companies.