Austria is working with US authorities to investigate a reported spate of suspected cases of an ailment known as "Havana syndrome" among US diplomats in Vienna, the Austrian Foreign Ministry says.
US Secretary of State Antony Blinken said last month his country is conducting a government-wide review into who - or what - caused what it suspects were "directed" radio frequency attacks on US diplomats that resulted in various neurological ailments that first emerged in the Cuban capital in 2016.
The New Yorker magazine said on Saturday that since US President Joe Biden took office in January, roughly two dozen US intelligence officers, diplomats and other officials in Vienna have reported symptoms similar to those of Havana syndrome, making it the second-biggest hotspot after Havana.
"We take these reports very seriously and in line with our role as host state we are working with the US authorities on jointly getting to the bottom of this," Austria's Foreign Ministry said in a short statement.
"The safety of diplomats posted to Vienna and their families is of the utmost importance to us."
A State Department spokesperson said the reported cases affecting officials at the US Embassy in Vienna are being "vigorously" investigated.
Once a centre of Cold War intrigue, Vienna is home to several UN agencies and the Organization for Security and Cooperation in Europe, meaning bigger countries, such as the US and Russia, often have three ambassadors and a large diplomatic presence in Austria's capital.
That has long made Vienna a hub for diplomatic activity and spying, since many spies operate under diplomatic cover.
The Austrian Foreign Ministry's website says 158 US diplomats are currently being posted in Vienna.