The foreign minister of the tiny South American nation of Guyana has said that neighbouring Venezuela is “on the wrong side of history” as it risks sparking conflict over an oil-rich and long-contested swath of rainforest. Tensions between the two countries have reached unprecedented heights ahead of a referendum on Sunday intended to rubber-stamp Venezuela’s claim on the region of Essequibo. Among the five questions President Nicolás Maduro is asking his citizens is whether they should convert the 160,000 sq km area into a new Venezuelan state. It remains unclear what the legal or practical implications of a yes vote would be, and the referendum is widely seen as a way for the deeply unpopular dictator to drum up public support ahead of presidential elections next year. But there are growing concerns that Maduro could push the country into war as he uses the century-old dispute to whip up patriotic fervour. “People in the border region are very concerned,” Guyana’s foreign minister, Hugh Todd, told the Guardian. “Maduro is a despotic leader, and despotic leaders are very hard to predict.” Venezuela has laid claim to the Essequibo ever since it gained independence from Spain in 1811. Inhabited by 120,000 of Guyana’s 800,000 people, the region is largely impenetrable jungle but has large reserves of oil, gold and copper. In 2018, Guyana asked the international court of justice (ICJ) to finally settle the matter, but the decision remains years away and Venezuela contests the court’s authority. Instead, Maduro is asking his citizens to decide on Sunday whether the government should ignore the international arbitrators, grant Venezuelan citizenship to Essequibo’s English-speaking inhabitants and convert more than two-thirds of Guyana’s territory into a new Venezuelan state. “They are asking the people of Venezuela to vote to annex our Essequibo, which is clearly not only against international laws and norms, but goes against the grain of the region being a zone of peace,” Todd said. On Friday the ICJ ordered Venezuela to “refrain from taking any action” that would alter Guyana’s control over Essequibo – although it did not forbid Sunday’s referendum. “The court observes that the situation that currently prevails in the territory in dispute is that Guyana administers and exercises control over that area,” said the presiding judge, Joan Donoghue. Venezuela’s government, however, interpreted the ruling as a victory, saying in a statement that the court had “rejected” Guyana’s request for the vote to be stopped. Past Venezuelan leaders have dredged up the dispute in times of domestic turmoil but perhaps none have campaigned as hard on the issue as Nicolás Maduro. The 61-year-old’s TikTok output has become increasingly prolific and his rhetoric more bellicose since 2015, when massive oil deposits were discovered in the contested region. Maduro has presented history lessons on state television, interrupted school classes to get young children to cheer on the country’s territorial claim and handed out revised maps depicting an engorged Venezuela straddling a Guyana a fraction of its internationally recognised size. The socialist government has also released a series of highly polished campaign videos of Venezuelan children playing in the lush forests and cascading waterfalls and an official song, The Essequibo is Ours. “It’s in your hands, compatriots,” Maduro pleads in one video, to the upbeat drumming of the catchy pop tune. “Vote five times yes!” Venezuela disputes the borders drawn by international arbitrators in 1899, when Guyana was a British colony, arguing that the agreement was annulled in 1966. Maduro has accused Guyana – along with the United States and international oil giants – of conspiring to rob Venezuela of its land through “legal colonialism”. Guyana points to the 1899 ruling and argues that any disputes should be resolved peacefully in The Hague. “The ICJ is the route that will bring finality to the controversy that Venezuela has over the validity of the 1899 award,” Todd said. “Our Essequibo belongs to the people of Guyana. Always has and always will,” he added. “The people who reside in that region speak English, they pay taxes to the government of Guyana, they abide by our constitution … and they call themselves Guyanese. So it has nothing to do with Venezuela.” Both sides blame each other for stoking regional tensions but analysts say Maduro –whose decade in power has seen the exodus of more than 7 million Venezuelans fleeing poverty and insecurity – has more to gain. The Essequibo is the only major issue in Venezuela which unites people across the political divide, said Phil Gunson, senior analyst at the International Crisis Group, adding that the government is using the issue to rally the population and gauge how many could be mobilised in next year’s presidential elections. A resounding yes vote on Sunday is a “foregone conclusion”, he said. “Venezuela has been disingenuous to its own people. It is using this referendum to boost President Maduro’s political image, because he has practically no platform to run on in elections but to use Guyana and its claim to our Essequibo,” Todd said. With “Cinco Veces Sí” a likely outcome on Sunday, the question for Guyana’s 800,000 people is: what happens next? “What does this mean for Guyana and its citizens, because there is a level of fear for that day and thereafter,” a concerned student in Georgetown asked a panel of experts last week. Analysts say that as diplomatic tensions rise it is increasingly difficult to see a way out which allows both sides to save face. The Guyanese president, Irfaan Ali, recently spent a night at a military camp on the border and the Venezuelan military built an airstrip near the contentious frontier. Venezuela’s interior minister, Vladimir Padrino López, has shown no interest in calming the rising tensions, telling his troops earlier this month: “We are ready to defend [Essequibo] to the last drop of blood and sweat.” Tensions between the two countries have never been so high, said one Venezuelan defence specialist. “It’s very alarming,” said Rocío San Miguel. “We are probably heading to a dead-end street where both sides have to protect their honour, and that is a dangerous place where, throughout history, irrational decisions have been taken.” Brazil sent troops to its northern border with Guyana and Venezuela on Wednesday as the dispute intensified, the country’s defence minister said. Though Venezuela, with its population of 28 million, would have the obvious military upper hand, the diplomatic costs of an invasion would be high. “Maduro would be totally isolated because he has virtually no support anywhere in the world – even among his own traditional allies such as Cuba,” Gunson said. Though Todd says Caracas’s ambassador to Georgetown has told the country’s leadership that Venezuela has no intention of invading, Guyana remains on high alert owing to Maduro’s unpredictability. “We have always said, and we mean it, that we want to resolve the controversy over the 1899 award peacefully. But while we believe that diplomacy is the best option, we are a nation state and we have to protect our people. Therefore we will not rule out any option necessary to ensure that we can protect and preserve our sovereignty and territorial integrity,” he said. With Venezuela isolated, Guyana is looking to its allies in the Caribbean Caricom community and the Commonwealth for support. Ahead of a visit from US defence officials this week, Vice-President Bharrat Jagdeo said the country has begun considering the need to host foreign military bases. “Any one of our international partners in the democratic free world will want to support Guyana’s cause, because we have always followed the rules, procedures and principles. Venezuela is doing the contrary to that. They are on the wrong side of international law and they are on the wrong side of history. They do not have friends and partners on the path that they are taking,” Todd said. As Venezuelans dance to ska and pop at the government-organised Essequibo Fest this weekend, the tone in Guyana is likely to be more solemn. The government is asking people to pray, and for the country’s Muslim, Hindu and Christian communities to come together in unity. “There is anxiety and disquiet for we do not know what Venezuela will do,” said the Rev Kwame Gilbert, who will be leading a ceremony from the centre of Georgetown. “We want to lift the spirits of all Guyanese in an environment of unity and solidarity. We are hopeful that diplomacy will prevail and hopeful that good sense will prevail.”