The United States has expelled 15 Cuban diplomats from the country’s embassy, less than a week after pulling its own embassy workers from Cuba in response to a series of apparent sonic attacks on American personnel.

American officials in Cuba have experienced a strange assortment of brain-related illnesses, from dizziness to fatigue to hearing loss, which intelligence officials believe resulted from a series of attacks by unknown agents. The United States announced last Friday it would reduce its Cuban diplomatic presence to a bare-bones group of 27 people left to carry out emergency services. The decision to expel Cuban diplomats is intended to force the Cuban government to operate their embassy under the same conditions, State Department officials said Tuesday.