A security guard stands outside the US Embassy in Havana, Cuba, December 12, 2017. (Reuters photo)

Electromagnetic energy pulses and ultrasound might have hit the American diplomats and spies who suffered from a mysterious illness known as Havana Syndrome, a US intelligence report says.

Havana Syndrome got its name after a group of diplomats and CIA officers reported symptoms in 2016 at the US Embassy in Cuba�s capital Havana.

Washington claims that the syndrome is a kind of neurological attack which has targeted the country�s spies and diplomats stationed in overseas locations.

According to the new report released on Wednesday by a panel of expert scientists, Pulse electromagnetic energy, particularly in the radio frequency range, plausibly explains the ear pain, vertigo, and other symptoms of some of those suffering the ailments first reported by US diplomats in Havana.

In a redacted executive summary of its report, the panel said that the signs and symptoms of the syndrome were diverse and may be caused by multiple mechanisms but that a subset of them cannot be easily explained by known environmental or medical conditions.

In finding that pulse electromagnetic energy might be the cause, the panel noted information gaps exist, however, there are several plausible ways the energy could have been generated each with its own requirements, limitations and unknowns.

The panel of experts was convened by Director of National Intelligence Avril Haines and CIA Deputy Director David Cohen.

The new findings echo a 2020 National Academy of Sciences study and follow an interim CIA report published on Jan. 20 that concluded that it was unlikely that Russia or another foreign country was behind most of the so-called anomalous health incidents.

However, according to the CIA report, there were about two dozen cases of the 1,000 that remained unexplained.

The report�s conclusions will probably fuel frustration among current and former US officials who lack a clear explanation for their chronic afflictions.

We were not looking at attribution or assigning it to a foreign adversary or actor. We stuck to the causal mechanism, a US intelligence official familiar with the report told reporters.

Back in 2018, NBC news reported that US intelligence consider Moscow as a suspect in what they alleged to have been deliberate attacks on American diplomats and CIA officers overseas.

Russia has consistently denied any culpability.

Experts argue that how it is possible that a secret Russian program that supposedly harm US spies and diplomats, could go completely undetected by the $80 billion US spying apparatus.