RIO DE JANEIRO - Brazilian President Luiz Inacio Lula da Silva urged his counterpart Nicolas Maduro Saturday against escalating Venezuela's border row with neighboring Guyana, as South American leaders nervously monitored the deepening dispute.
Tension has soared over the oil-rich Essequibo region controlled by Guyana since Maduro's government held a controversial referendum last weekend in which 95 percent of voters supported declaring Venezuela its rightful owner, according to official results.
Veteran leftist Lula, who has maintained close ties with Maduro, issued a clear warning in a phone call with his Venezuelan counterpart, according to a statement from his office.
"Lula emphasized the importance of avoiding unilateral measures that could escalate the situation," the Brazilian presidency said.
It said Lula had told Maduro of fellow South American countries' "growing concern," citing a joint declaration Thursday by Argentina, Brazil, Chile, Colombia, Ecuador, Paraguay, Peru and Uruguay that called for "both parties to negotiate to seek a peaceful solution."
Colombian President Gustavo Petro also sent a warning.
"The biggest misfortune that could hit South America would be a war," he wrote on X, formerly Twitter.
"Reproducing a local version of the NATO/Russia conflict in the Amazon rainforest would just make us lose vital time, progress and life... Venezuela and Guyana need to de-escalate the conflict."
- Calls for mediation -
Guyana has administered Essequibo, which makes up more than two-thirds of its territory, for more than a century.
But Venezuela has claimed it for decades. The row intensified after ExxonMobil discovered oil in Essequibo in 2015, helping give Guyana -- population 800,000 -- the world's biggest crude reserves per capita.
Since last Sunday's referendum, Maduro has started legal maneuvers to create a Venezuelan province in Essequibo and ordered the state oil company to issue licenses for extracting crude in the region.
The United States meanwhile announced joint military exercises with Guyana, which Venezuela condemned as a "provocation."
The United Nations Security Council held a closed-door meeting Friday on the spiraling dispute, which is the subject of litigation before the International Court of Justice (ICJ).
Lula's office said he had proposed in his conversation with Maduro for the head of the Community of Latin American and Caribbean States to contact both sides to set up talks.
Lula has so far kept friendly ties with Maduro, inviting him to a South American summit in May even as other regional leaders criticized the Venezuelan government's human rights record.
But the Essequibo dispute is rife with risk for Brazil, which borders both Guyana and Venezuela.
Brazil has sent army reinforcements to its northern border amid the surge in tension.