'Handful' of US citizens reported health attacks after visiting Cuba, State Dept. says The claims have not been verified.

 -- One week after the Trump administration issued a travel warning for Cuba, it said that a "handful" of Americans who traveled to the island country reported to the State Department that they "experienced symptoms similar" to those affecting nearly two dozen embassy personnel in Havana.

Twenty-two American government employees have been hit by "targeted" attacks, with symptoms ranging from dizziness, to headache and fatigue, to hearing loss, to traumatic brain injury. But, if verified, the claims in the statement from the State Department would mark a dramatic escalation of the ongoing mystery that has vexed U.S. investigators and so far only affected government personnel.

"A handful of U.S. citizens who recently traveled to Cuba have communicated to us that they experienced symptoms similar to those listed in our Sept. 29 travel warning," a State Department official told ABC News. "We cannot verify the claims and continue to urge American citizens to review our travel warning prior to traveling to Cuba."

In contrast, Secretary of State Rex Tillerson said in a statement just last week, "We have no reports that private U.S. citizens have been affected," although some attacks have occurred in hotels reportedly frequented by American tourists.

Despite the lack of evidence Americans in general are being targeted, a senior administration official said last week that the department felt compelled to issue the warning because the government is still unable to determine a cause or source.

Along with the warning, the agency announced it was withdrawing all but its emergency personnel at the embassy in Havana and suspending all visa issuances there.

State Department spokesperson Heather Nauert maintained that the U.S. does not find Cuba guilty of the attacks, but does hold them responsible for protecting American diplomats on their soil.

"This is not a punishment. Cuba, we are not going to say, is responsible for these attacks," she told reporters Tuesday.

The investigation by the FBI and State's Diplomatic Security remains ongoing, with no source or responsible party determined.