The U.S. drew down its diplomatic footprint in Havana by about 60 percent last year after a series of mysterious illnesses that affected its personnel. There is still no known cause for the spate of ailments, which included hearing loss, nausea and difficulties walking.
Those affected reported hearing a high pitched sound before falling ill, but little else is known about the mysterious events. Cuba has denied any involvement or knowledge of the attacks. An investigation is ongoing.
The new staffing plan will take effect March 5 after the initial six-month drawdown window draws to a close Sunday.
"The embassy will continue to operate with the minimum personnel necessary to perform core diplomatic and consular functions, similar to the level of emergency staffing maintained during ordered departure," the State Department said in a statement.
No family will be allowed to accompany diplomatic staff stationed at the U.S. embassy, according to the department.
"The health, safety, and well-being of U.S. government personnel and family members are of the greatest concern for Secretary [of State Rex] Tillerson and were a key factor in the decision to reduce the number of personnel assigned to Havana," the agency added.