OTTAWA, Canada (AFP) — Mysterious “sonic attacks” in Cuba in recent months targeted at least five Canadian diplomats and their families, public broadcaster CBC reported Friday.

The incidents were first revealed at the beginning of August when Canadian and US officials said they had launched an investigation into the cause of diplomats’ sudden hearing loss, migraines and nausea in Havana.

At the time, Ottawa confirmed that one of its envoys had been treated for the symptoms.

“More than five, but fewer than 10 Canadian families were affected by the attacks,” CBC said Friday, citing an unnamed source.

In some cases, hospitalisation was required, the public broadcaster said, adding that all of the Canadians have recovered from the initial symptoms.

The US State Department has said 16 Americans were affected in the “incidents,” which appear to have begun in 2016.

“We are aware of unusual symptoms affecting Canadian and US diplomatic personnel and their families in Havana,” Canadian foreign ministry spokeswoman Brianne Maxwell said last month.

The diplomats reported hearing loud grinding or ringing noises, or feeling vibrations in their bodies.

Canadian authorities said Cuban officials are not suspected and have been cooperating in the investigation.

In contrast to the long-thorny US-Cuban relationship, Ottawa and Havana have generally had warm relations.