WASHINGTON (NewsNation Now) — Lawmakers are looking into what they believe are targeted attacks on U.S. diplomats. Several officials have reported mysterious brain injuries that could be tied to the use of microwaves.

The most recent example happened roughly five years ago at the U.S. embassy in Havana, Cuba. More than 20 diplomats reported strange symptoms now known as the “Havana syndrome.”

On Thursday, the CIA Director updated members of Congress on his response to the attack.

“I’ve met with three different groups over several hours with my colleagues, going back to Havana who have been affected by these incidents, simply to make clear to them not only my personal priory but that we take very seriously what they’ve experienced and have enormous respect for their sacrifice and their dedication and that we will get to the bottom of this,” said CIA Director Williams Burns.

Diplomats working in China and Moscow have reported similar brain injuries after their work abroad.

Executive News Editor at Foreign Policy and author Sharon Weinberger, a specialist in defense and intelligence coverage, says we know very little about what actually happened in the attacks.

“There’s a lot of secrecy around the personnel because we now know through reporting these were primarily CIA personnel. Even the National Academy of Sciences, which was asked to review a good part of this issue, did not have access to the people who were actually affected,” said Weinberger.

She added, “I mean clearly there are U.S. government personnel who have suffered health effects… we need to start without presuming what the cause is and try to find out what these personnel are suffering from.”

She believes it is a possible, but “far-fetched possibility,” that this was caused by a microwave weapon.

“And if we pursue only that line of investigation and it turns out it was something else, a toxin or an insecticide or something that poisoned them. These people are not getting treatment,” said Weinberger.