Colombian President Ivan Duque has stated that his administration is aware of cases of so-called Havana syndrome at the US embassy in Bogota, but that the inquiry would be handled by Washington.

According to the Wall Street Journal, at least five US families affiliated with the embassy in Colombia have developed symptoms of the unexplained illness, which include headaches, nausea, and possibly brain damage.

"Of course, we have knowledge of this situation, but I want to leave it to the US authorities, who are doing their investigation because it is about their personnel," Duque told reporters in New York during an official US visit in which he has also visited Washington.

The Colombia cases are only the most recent in a string of dozens of Havana syndrome incidents involving US diplomats and intelligence personnel since 2016 – first in Cuba, then in China, Germany, Australia, Taiwan, and Washington, DC.

Last Monday, US President Joe Biden signed legislation giving financial assistance to patients of the mystery sickness.

The Havana Act compensates members of the State Department and CIA who suffer brain injuries as a result of what officials think are directed microwave assaults.

"Civil servants, intelligence officers, diplomats, and military personnel all around the world have been affected by anomalous health incidents," Biden said in a statement.

"Some are struggling with debilitating brain injuries that have curtailed their careers of service to our nation."

The cause of the diseases has not yet been determined, and the name of the attacker, if any, has not been divulged.

The Cuban authorities examined the situation and consistently dismissed US allegations as false.

In addition to professional diplomats and employees, the US Embassy in Bogota, one of the largest in the world, has a substantial number of agents engaged in both intelligence and counter-narcotics activities.

On October 20, Secretary of State Antony Blinken is expected to visit the nation.