Cuban authorities on Sunday disclosed new details on an unexplained illness affecting U.S. diplomats, saying a female U.S. embassy worker had complained of “undefined sounds” late last month. The unidentified staffer’s complaints prompted a visit from Cuban investigators but no explanation was found for the sounds, the foreign ministry said in a statement. The details come after the State Department on Friday announced two “potentially new cases” of the bizarre ailment that, if confirmed, would bring the total tally to 26. The two latest victims of the so-called “sonic attacks” were reportedly recalled for medical testing on May 29. The U.S. pulled nearly two dozen staffers out of Cuba late last year over the unexplained ailment, which has reportedly left victims with neurological damage. The new cases come amid a U.S. health alert in China after staffers there began complaining of similar health problems. U.S. authorities have described the illness as a result of “specific attacks” but have yet to determine who is behind them.