Global Affairs Canada gave no details. But a spokeswoman said officials 'are aware of unusual symptoms affecting Canadian and U.S. diplomatic personnel and their families in Havana. The government is actively working, including with U.S. and Cuban authorities, to ascertain the cause.'
Canada's disclosure came a day after the U.S. State Department said it had expelled two Cuban diplomats from Washington in May over what it would describe only as a 'variety of physical symptoms' suffered by U.S. diplomats at the embassy in Havana.
A spokeswoman gave no more information. But a State Department official said someone placed an inaudible sonic device either inside or outside U.S. diplomatic residences in Havana.
The device caused hearing loss, headaches, sleeplessness and general disorientation, and forced several U.S. personnel to return home early.
It was unclear who ordered such actions against the Americans and why. But Cuba's Foreign Ministry sent out a statement saying the highest levels of its government had ordered an investigation.
The statement said Cuba never had and never would allow its territory to be used for 'any action against accredited diplomatic officials or their families, without exception.'
It said that Cuba seriously complies with the Vienna Convention on Diplomatic Relations and that 'its impeccable performance in this area is internationally recognized.'
The ministry said Cuba was a safe place for foreign visitors and diplomats, and it called the U.S. expulsion of the two Cubans from Washington 'unjustified and groundless.'
Despite Cuba's assertion that there has never been action taken against diplomats on Cuban soil, experts say such tactics as harassing Americans were common before the U.S. and Cuba re-established diplomatic ties two years ago.
But the harassment was never intended to cause physical harm.