During a classified briefing on Thursday, Deputy CIA Director David Cohen and Assistant FBI Director Alan Kohler told senators the United States will soon be issuing its payments to U.S. diplomats and intelligence officials who have been victim to the mysterious illness while working abroad, known as “Havana Syndrome” reports NBC News.

Thursday’s information is the latest on the ongoing investigation over the past few years into what the Biden administration calls “anomalous health incidents.” NBC News reports:

It was unclear what information they provided about the investigation into the incidents, which remain unexplained more than five years after U.S. diplomats and spies in Havana began to report experiencing strange sounds and sensations followed by a variety of symptoms, including brain injury. U.S. officials familiar with the investigation say the U.S. has still not determined a cause.

State Department and CIA officials told senators that within days, the administration will release a plan to compensate U.S. personnel who have suffered injuries and how much to pay them, with some payments expected to exceed $100,000 per person, people familiar with the briefing said.

Payments are under the umbrella of the HAVANA Act which Biden signed into law last year. The act gives the secretary of state and the CIA the power to determine eligibility for the payments; “a thorny task given the wide disagreement over what should be considered legitimate, ‘confirmed’ cases.”

Not only are the legitimacy of the cases in question, as well as the dollar amount range to be given in each case, but “the Biden administration has already missed an April deadline to propose a system for who will be eligible and for what sum.”

NBC adds that the State Department declined to comment on the briefing with senators and said it would release more information about the compensation proposal “soon.”

“The department is doing everything possible to ensure that employees who report an AHI receive immediate and appropriate attention and care,” a State Department spokesperson said, using an initialism for “anomalous health incident.”

A provision added to the annual military spending bill by Senators Jeanne Shaheen, D-N.H., and Susan Collins, R-Maine, requires the administration to brief lawmakers periodically about the status of the investigation.