The United States has been working with the United Kingdom to hack Israeli drones and spy on them for nearly two decades, according to documents released this week, under a classified program called “Anarchist,” according to a report.

“Anarchist operated from a Royal Air Force installation in the Troodos Mountains, near Mount Olympus, the highest point on Cyprus,” The Intercept reported on Thursday. It has long been known that the base has strategic value in conducting surveillance in North Africa, Turkey and the Levant.