WASHINGTON — State Department officials are investigating health-related incidents that caused some American diplomats and their families to leave Cuba, but they refused on Thursday to identify any particular country or cause as a source for the ailments.

Officials also did not release the number of Americans affected.

“Some Americans chose to go home, come home as a result of that,” Heather Nauert, a State Department spokeswoman, said of the health issues.

In response, the State Department expelled two Cuban diplomats from the embassy in the United States on May 23.