Dozens of U.S. diplomatic personnel and officials stationed in Vienna have experienced “unexplained health incidents” similar to the ailments first reported in Havana in 2016, according to The New Yorker. With the number of cases reported in Vienna—two dozen—second only to those in the Cuban capital, the CIA and the State Department are said to be intensifying their efforts to determine who and what is behind the mysterious afflictions. CIA director William Burns is said to be “personally engaged with personnel affected by anomalous health incidents and is highly committed to their care and to determining the cause of these incidents.” So far, U.S. officials have described the Vienna episodes only as “anomalous health incidents,” though Burns reportedly described the ailments as “attacks” in private. The so-called Havana Syndrome first triggered alarm bells among U.S. intelligence in 2016, when diplomatic personnel in the Cuban capital began reporting unexplained symptoms like ringing in their ears, migraines, and loss of balance, among other things. Dozens of U.S. diplomats and officials have since reported experiencing similar ailments, which are widely believed to be the result of directed-energy attacks. In some cases, the individuals affected were left with permanent brain injuries and chronic illness.