A mysterious illness that has affected US diplomats in recent years has been linked to a Russian intelligence unit.

Personnel stationed around the globe with “Havana Syndrome” have reported unexplained symptoms such as dizziness.

They may have been targeted by Russian sonic weaponry, according to a joint investigation by The Insider, Der Spiegel and CBS’s 60 Minutes.

There has long been a suspicion that those affected have been hit by directed energy or microwaves fired from hidden devices - a possibility that was acknowledged in an earlier US intelligence report.

The fresh media investigation alleges that operatives from a Russian military intelligence unit - known as 29155 - may have targeted the brains of US diplomats with “directed energy” weapons.

It says there is evidence that places members of the unit in cities around the world at times when US personnel reported incidents.