Follow CBSMIAMI.COM: Facebook | Twitter

WASHINGTON (CBSMiami) — The United States have expelled two Cuban diplomats as federal investigators look into strange illnesses involving U.S. diplomats in Havana.

READ MORE: Officials: Man On American Airlines Flight From Guatemala Hitched Ride To Miami Inside Plane's Landing Gear

State department employees in Havana began complaining of hearing loss, constant painful headaches, and other issues late last year.

A source familiar with the matter tells CBS News that U.S. officials are now looking into whether the incidents were caused by a possible type of acoustics device that was in, or outside, homes of embassy workers provided by the Cuban government.

“Initially when they started reporting what I will just call ‘symptoms,’ it took time to figure out what it was and this is still ongoing,” said State Department Spokesperson Heather Nauert.

READ MORE: Assisted Living Facility In Lauderhill May Lose License After Woman Dies

CBS News has learned as many as eight or nine U.S. diplomats had their assignments cut short because of their ailments.

But some affected employees still remain on the island.

“We have some Americans who choose to come home as a result of that,” said Nauert. “And as a result of that, we’ve asked two Cubans to leave the United States and they have.”

The development comes just two months after President Donald Trump tightened travel and trade restrictions that were loosened under former President Obama. Cuba’s foreign ministry said that in February it launched an “urgent investigation at the behest of the highest level of the Cuban government” into the incidents, adding that the country would never allow actions against diplomats and their families on its soil.

MORE NEWS: Boca Raton Man Faces Charges In Fatal Crash That Killed Homestead Mom, Daughter On Thanksgiving Eve

Sources also tell CBS News that a Canadian embassy employee also reported headaches and hearing loss. Security has since been increased around the U.S. embassy and diplomatic homes in Havana.