Cuba-US relations history
19 July 2015: A Cuban flag flies in front of the US Interests Section in Havana the day before it was formally reopened as an embassy Alexandre Meneghini/Reuters

A recorded sample of the mystery audio generated by an "advanced sonic weapon" that left several members of the US Embassy in Cuba with hearing loss in August has been released by the AP news agency.

In an incident that seems like something out of a Cold War-era spy movie, the sound recording was – according to a report by Task and Purpose quoting AP – "what some US Embassy workers heard in Havana", and is now in the hands of US military analysts and intelligence services.

The report mentions that the audio generated by the "advanced sonic weapon that operated outside the range of audible sound" was recorded by US authorities, but that this recording has been modified to make it audible and quite clear. Also, this released sample is not dangerous for people to listen to. This is possibly due to the digital enhancements and alterations made to reduce background noise and increase its volume.

Two weeks after news of the incident first broke out in August, it was reported that US and Canadian diplomats suffered brain damage because of this mysterious sound-based weapon. By the end of September, many officials were pulled out of the US Embassy in Cuba after "dozens fell ill".

Nearly half the staff was eventually withdrawn from the embassy and tourists were warned about keeping away from the area.

Cuba, as expected, has denied any involvement with what the US is calling "specific attacks".

According to a September 29 statement, the US State Department said, "Over the past several months, at least 21 US embassy employees have been targeted in specific attacks. The health, safety, and well-being of our embassy community are our greatest concerns. Investigations into the attacks are ongoing, as investigators have been unable to determine who or what is causing these attacks."

The statement also mentioned that the embassy will operate at a reduced capacity, using only emergency personnel, until the situation is sorted out. The government also restricted short-term travel to the island by US officials.

When asked about Russian involvement, or the chances of a "third country" being responsible for the attack, the response given by the State Department was that they "have not ruled out the possibility". Asked about whether or not the embassy will be closed down, the response was that it would remain open, but with only emergency staff to "provide basic services to American citizens and fulfil our diplomatic mission".

The US embassy in Cuba was opened after 54 years in 2015. It was seen as a milestone in easing diplomatic relations between the two countries.

Here's a version of the audio clip which has been modified and is NOT dangerous for people to listen to: