Over 20 US officials in Vienna, Austria, have reported symptoms like that of a mysterious brain illness – Havana Syndrome. The cases have been on the rise since US President Joe Biden took office in January 2021, BBC reported.

Although mysterious, scientists in the US claim that the syndrome is likely caused by direct microwave radiation. The first occurrence of the illness dates back to 2016-17 in Cuba.

Diplomats and administration staff in Havana reported symptoms like loss of balance, hearing loss, dizziness, and cognitive fog. This led to the US accusing Cuba of carrying out ‘sonic attacks’, resulting in growing tension between the two countries.

Also Read | Cuban president denounces unrest as a ‘lie’

The US State Department on July 16, 2021, confirmed the first case of Havana Syndrome and claimed to be investigating it vigorously. Their spokesperson said, “In coordination with our partners across the US government, we are vigorously investigating reports of possible unexplained health incidents among the US Embassy Vienna community.”

According to Reuters, a foreign ministry statement said it was “working with the US authorities on jointly getting to the bottom of this”.

Known to be a hotspot for espionage, Vienna remains the centre for diplomatic activity, with the US observing a massive diplomatic presence in the country.

Also Read | Biden says US considering whether it can reinstate internet access in Cuba

Furthermore, In an interview with The New Yorker, a CIA spokesperson said, “Agency’s director, William Burns, was personally engaged with personnel affected by anomalous health incidents and is highly committed to their care and to determining the cause of these incidents.”

Although cases of Havana syndrome have been reported in many parts of the world, Vienna remains the one where the number of cases is greater than others, according to US officials. Hence, US Secretary of State Antony Blinken announced a review of the issue, to track the cause and identify the culprit of the situation.