Venezuela will hold a referendum on Sunday on whether to create a new state in a disputed, oil-rich territory long ruled by Guyana.

The vote takes place according to the International Court of Justice (ICJ) Venezuela urged not to take any action that could change the status quo in the region. However, Caracas was not specifically banned from holding the referendum, as Guyana had requested.

Friday’s ruling is the latest development in the larger border dispute. The ICJ said in April that it had jurisdiction over the case but that a final decision could be years away.

Here’s what you should know about the vote and the dispute.

A referendum in Venezuela

Venezuela will hold a referendum on December 3 on its rights to a potentially oil-rich area that is the subject of a border dispute with Guyana.

The referendum will ask Venezuelans five questions, including whether they agree to the creation of a new state called Guayana Esequiba in the Essequibo region, granting its people Venezuelan citizenship and identity cards and include insert this state into the map of Venezuelan territory.

Guyana fears the referendum could be a pretext for a land grab. “The collective decision called for here involves nothing less than the annexation of the territory in dispute in this case,” Paul Reichler, an American lawyer representing Guyana, told the International Court of Justice. “This is a prime example of annexation.”

The Venezuelan government has not explained how it would create the state if voters approved it. The referendum is also called consultative.

The ICJ said There is a “serious risk that Venezuela will acquire and exercise control and administration of the territory disputed in the present case.”

Political analysts expect voters to approve the proposal because there is no “no” campaign and the likelihood that voters who oppose it will stay home.

Dispute between Venezuela and Guyana

Caracas considers Essequibo to be its own territory, as the region was within its borders during the Spanish colony.

The Guyanese government insists on maintaining the border set by an arbitration tribunal in Paris in 1899, but claims that Venezuela agreed with the decision until it changed its mind in 1962.

Caracas claims that the Essequibo River forms a natural border to the east of the region and has been recognized as such since 1777.

It rejects the 1889 ruling. During these negotiations, the United States represented Venezuela on the panel, in part because the Venezuelan government had severed diplomatic relations with the United Kingdom.

Venezuelan officials claim the Americans and Europeans conspired to defraud their country of the land and argue that a 1966 agreement to resolve the dispute effectively nullified the original arbitration process. Guyana insists that the original agreement was legal and binding.

Tensions between the countries have increased since 2015 due to oil exploration activities by ExxonMobil and other companies in offshore areas that intersect the disputed area.

The Venezuelan government maintains that Guyana does not have the right to grant concessions in marine areas of the Essequibo.

The relevance of the Essequibo

Larger than Greece, the area known as “Essequibo” accounts for more than two-thirds of Guyana’s territory and is home to 125,000 of Guyana’s 800,000 residents.

The 159,500 square kilometer area lies in the heart of the Guiana Shield, a geographical region in northeastern South America and one of the last four untouched tropical forests Natural and mineral resources are being mined in the world, including large reserves of gold, copper, diamond, iron and aluminum, among others.

The region also has the world’s largest crude oil reserves per capita. Just last month, Guyana announced a “significant” new oil discovery that brings estimated reserves to at least 10 billion barrels – more than Kuwait or the United Arab Emirates.

With these resources, the country is forecast to surpass Venezuela’s oil production by 2025 is on the right track to become the world’s largest per capita crude oil producer.

Exxon and its partners – US-based Hess Corp and China’s CNOOC – are the only active oil producers in Guyana. Its projects are expected to reach production of 1.2 million barrels per day by 2027, making Guyana one of Latin America’s most significant producers, surpassed only by Brazil and Mexico.

International reactions

Brazil’s top diplomat for Latin American affairs, Gisela Maria Figueiredo, said on Thursday that President Luiz Inacio Lula da Silva’s government was monitoring the situation with “concern.”

In the United States, which has close ties with Guyana, National Security Council spokesman John Kirby called for a peaceful solution to the dispute.

Analyst Rocio San Miguel from the Citizen Watchdog on Security, Defense and the Armed Forces said that while Venezuela has significantly more military power than Guyana, it is unable to stand up to Guyana’s allies, which include the United States.