New Delhi, Feb 3 (IANS): An intelligence panel investigating the cause of a spate of mysterious incidents that have struck dozens of US officials across the globe has said that some of the episodes could "plausibly" have been caused by "pulsed electromagnetic energy" emitted by an external source, according to an executive summary of the panel's findings released Wednesday, CNN reported.

But the panel stopped short of making a definitive determination, saying only that both electromagnetic energy and, in limited circumstances, ultrasound could explain the key symptoms -- highlighting the degree to which the murky illness known colloquially as "Havana Syndrome" has remained one of the intelligence community's most stubborn mysteries, the report said.

"We've learned a lot," an intelligence official familiar with the panel's work told reporters, speaking on anonymity under terms set by the Office of the Director of National Intelligence. "While we don't have the specific mechanism for each case, what we do know is if you report quickly and promptly get medical care, most people are getting well.

The finding largely confirms a National Academies of Science report from late 2020 that found "directed, pulsed radio frequency energy" to be "the most plausible mechanism in explaining these cases" -- but also stopped short of making a firm determination.

A report by a separate CIA task force examining who might be behind the episodes found that it was unlikely Russia or any other foreign adversary is conducting a widespread global campaign designed to harm the US officials. But the agency also did not rule out that a nation state -- including Russia -- might be responsible for roughly two dozen cases that investigators have been unable to explain by any other known cause, the report said.