WASHINGTON, D.C.: US and Canadian officials were investigating Thursday (Friday in Manila) after diplomats posted to Havana fell ill, amid reports that they may have been targeted by a mysterious sonic weapon. US officials refused to directly blame Cuba itself for the “incidents,” which appear to have begun last year, and Havana insisted it is working to protect the US mission. A State Department spokeswoman would not detail the nature or number of the injuries, but she confirmed that a number of US diplomats had returned home for treatment. Meanwhile, Canada confirmed that one of its envoys had suffered a similar incident. “We are aware of unusual symptoms affecting Canadian and US diplomatic personnel and their families in Havana,” Canadian foreign ministry spokeswoman Brianne Maxwell said.Some countries have developed sonic and ultrasonic weapons that can be used for crowd control or, for example, to deter seaborne pirates without resource to lethal force.