US official who travelled reported symptoms consistent with Havana syndrome and had to receive medical attention, US media outlets reported.
CIA Director Bill Burns traveled to India earlier this month for talks with Indian counterparts.
Some officials at the CIA viewed the chilling episode as a direct message to Burns that no one is safe, including those working directly for the nation’s top spy.
The event marks the second time in less than a month that reported cases of the mysterious illness have impacted the international travel of top Biden administration officials.
Last month Vice President Kamala Harris’s visit to Vietnam was slightly delayed when multiple US personnel reported symptoms consistent with the syndrome just ahead of her visit, and at least two of them had to be medically evacuated.
Under Burns and the Director of National Intelligence, Avril Haines, the intelligence community has undertaken a wide-ranging investigation into the mysterious attacks, including a 100-day probe into the potential causes that began earlier this summer. The investigation is expected to be concluded before the end of the year, reports said.
“We don’t comment on specific incidents or officers. We have protocols in place for when individuals report possible anomalous health incidents that include receiving appropriate medical treatment,” a CIA spokesperson said.
“We will keep doing everything we can to protect our officers.”
The situation in India could have dramatic implications: the CIA director’s schedule is tightly held and there are deep concerns among US officials about how the perpetrator would have known about the visit and been able to plan for such an aggression.
The person traveling with Burns who experienced the symptoms in India received immediate medical attention when they returned to the US.
US investigators have struggled to determine what or who is causing the mysterious symptoms, and how exactly they are doing it. Incidents of Havana syndrome began in late 2016 in Cuba and there have since been cases reported in Russia, China, Austria and other countries across the globe.