Havana, Cuba
Credit: Jeremy Woodhouse/Getty Images/Blend Images

The United States government is warning citizens against visiting Cuba following a series of bizarre “incidents.”

According to the Associated Press, the U.S. Department of State issued a travel warning on Friday, citing a series of “specific attacks” on U.S. embassy employees, some of which occurred in Cuban hotels.

“Affected individuals have exhibited a range of physical symptoms including ear complaints and hearing loss, dizziness, headache, fatigue, cognitive issues, and difficulty sleeping,” the State Department warning notes. “We believe U.S. citizens may also be at risk and warn them not to travel to Cuba.”

On Friday, approximately 60 percent of non-essential staff at the U.S. embassy in Havana were ordered to leave.

For more than a year, the U.S. has been investigating these incidents, according to the AP, which reportedly caused health problems for more than 20 staff members and their families. Authorities have not yet determined the cause of these incidents, which began some time in late 2016, according to the BBC. Vague “sonic attacks” were initially blamed for the symptoms, which ranged from concussions and hearing loss to nausea and dizziness.

As a result of the incidents, the U.S. will also immediately stop issuing visas for Cuban citizens in Cuba. The U.S. citizen’s services department, CNN noted, was already closed while repairs were being made following Hurricane Irma.

But the utter strangeness of the situation has not gone unnoticed. Following the announcement, members of American Tour Operators of Cuba (ATOC) released a statement on Twitter condemning the travel warning as, at best, an "overreaction."

ATOC, an association of tourism professionals and U.S. tour companies that offer travel services to Cuba, described the travel warning as "difficult to understand," as the "mysterious incidents...never posed a tangible threat to American visitors in Cuba."

"Today's Travel Warning unfairly sows fear and uncertainty, based on poor logic and evidence, and thus undermines the public's confidence and trust in the U.S. Department of State," ATOC concluded.

The decision to remove personnel from Havana could further strain tensions between Cuba and the United States. Former President Obama just reopened the embassy in 2015, and President Trump has been outspoken about his interest in rolling back his predecessor's Cuba policies.

Just over a year ago, the first scheduled commercial flight from the U.S. to Cuba in half a century landed in Santa Clara — a reminder of just how new and fragile the relationship is between the two countries.