15 September, 2017
But a Canadian source with knowledge of the affair told CBC News that unlike some of those US diplomats, all affected Canadians have recovered from their initial symptoms, which in some cases required hospital treatment.
The US has confirmed the number of employees affected has now risen to 21 and could rise further. The officials who were not authorised to speak on the record said that "at least some of the incidents were confined to specific rooms or even parts of rooms with laser-like specificity, baffling USA officials who say the facts and the physics don't add up". Some suffer from mild brain trauma, known as a concussion, and others suffered from permanent hearing loss.
The AP spoke with more than a dozen people from the USA and Cuba who have been briefed on the investigation into exactly what's happening to the diplomats that have been sent to Havana.
In May, Washington expelled two Cuban diplomats in protest of the communist government's lack of protection for the Americans working on the island.
Ms Nauert said other USA victims had been tested in Cuba, where the embassy has a full-time medical officer. Several victims reported they came in minute-long bursts. But inspections of those locations by the Federal Bureau of Investigation and the Royal Canadian Mounted Police have turned up nothing.
The source, speaking on condition of anonymity, said more than five - but fewer than 10 - Canadian families were affected by the attacks.
In one case, an American was jolted from his bed in a Havana hotel by a blaring, grinding noise. He moved just a few feet, and there was silence. It returned when he stepped back into bed.
According to several officials, some of the victims now have trouble concentrating or remembering specific words. However, others did not hear or feel anything, but they did show symptoms. The list of afflictions has expanded to include "brain swelling, dizziness, nausea, severe headaches, balance problems and tinnitus, or prolonged ringing in the ears".
Investigators have also tested conspiracy theories ranging from an intentional attack by Cuba's government, a rogue faction of its security forces, a third country like Russian Federation, or some combination of those possibilities.
US Secretary of State Rex Tillerson has called on Cuba to find the culprits. It doesn't know how the attacks happened, who is responsible, or why they did it.
Some Cuban officials have dismissed the United States response as an overreaction.
A senior Canadian diplomat who served in the embassy in Havana said the Cubans have an active and sometimes ruthless intelligence apparatus, and certainly engage in espionage of foreign diplomatic missions.
The officials said the incidents occurred in the homes of the USA officials, and in at least one hotel: the recently renovated Hotel Capri.
One of the incidents occurred on one of the upper floors of the newly remodeled Hotel Capri, a 60-year-old concrete tower just steps from the iconic Malecón de La Habana.
But in other respects the cases are different, with different symptoms and different memories of how the attacks transpired.
In some cases, they heard loud grinding or ringing noises, or felt vibrations in their bodies.
That is a larger number of people than previously reported and suggests the Canadian diplomats were targeted intentionally and were not merely victims of mistaken identity in a wave of attacks that affected a larger number of USA diplomats.
Scientists and acoustic experts are baffled by the attacks.
Another nation that has often been mentioned in connection with this case is Russian Federation, which has a large diplomatic presence in Cuba, poor relations with both the USA and Canada, and an alleged track record of dirty tricks and harassment of foreign diplomats.
That Canadians were caught up has muddied the waters; Canada has a good relationship with Cuba.
