The United States said it will carry out military flights in Guyana on Thursday in a joint operation as the South American country faces soaring tensions with neighboring Venezuela over a contested oil-rich region. “In collaboration with the Guyana Defence Force, the U.S. Southern Command will conduct flight operations within Guyana on December 7,” the American embassy in Guyana said in a statement, noting the flights are part of “routine engagement” to enhance a security partnership between the two countries. A border feud has recently spiraled over the oil-rich Essequibo region, controlled by Guyana for more than a century but which Venezuela also claims and has voiced intent to take over. The long-running dispute over Essequibo, which comprises some two-thirds of Guyanese territory, has intensified since ExxonMobil discovered oil there in 2015. Venezuelan President Nicolas Maduro has raised the pressure in recent days after gaining overwhelming support in a referendum on Essequibo’s fate that was held Sunday. Essequibo is home to 125,000 of Guyana’s 800,000 citizens. Litigation is pending before the International Court of Justice (ICJ) in The Hague over where the region’s borders should lie.