Mysterious 'Havana Syndrome' has been making US diplomats sick for years. Scientists finally have an explanation, report says.

• In 2016, US diplomats in Cuba reported the sudden onset of a painful set of symptoms. Similar symptoms were later identified in diplomatic personnel at an embassy in China.
• The mystery illness, which causes dizziness and tinnitus, has been dubbed the 'Havana Syndrome'.
• A study by the National Academies of Sciences considered four possibilities to explain the symptoms, reports NBC News.
• US government officials have been trying to get to the root of it for years. Now scientists think 'directed' microwaves could explain it, according to the study.

"Directed" microwaves are the most plausible explanation for a mystery illness suffered by US diplomats stationed in embassies across the world, according to a new study.

The study, which was first obtained by NBC News, explored four possible explanations for the so-called 'Havana Syndrome.'

A team of scientists from the National Academies of Sciences looked into whether it could be explained by infection, chemicals, psychological factors, or microwave energy.

At least 40 State Department officials were examined as part of the study, according to Axios.

The report, which was released on Saturday, concludes that directed microwave radiation is a more likely cause of the symptoms than the other three theories.

Although no country is directly blamed, the study notes that "significant research" has been carried out in Russia into the effects of this type of exposure.

The 'Havana Syndrome' has been somewhat of an enigma to scientists and government officials since it was first identified in 2016.

The illness, which causes a wide array of painful symptoms, was first reported by a US diplomat based in Cuba.

In the following three months, at least three other CIA officers complained of experiencing similarly "troubling sensations". They were all based in the same Havana embassy, according to the New Yorker.

Those suffering from it struggled with the sudden onset of loud noises, pain in both ears, dizziness, tinnitus, vertigo, and cognitive difficulties, the study states.

In 2017, little was known about the cause of the Havana Syndrome but President Donald Trump used a Rose Garden press conference to accuse Cuba of carrying out "sonic attacks."

Cuban officials denied this and called the allegations "science fiction" and "slander."

In the same year, diplomats at the US consulate in Guangzhou, China were removed after reporting symptoms of the unusual illness.

The release of this report follows years of investigation by US government officials. In October, Mike Pompeo admitted that "significant US government resources" had been dedicated to solving the mystery of the Havana Syndrome.