What is Havana Syndrome? Pentagon tests covert device suspected in mystery ailments affecting US spies and troops

What is Havana Syndrome? The US Defense Department has quietly spent more than a year testing a highly sensitive electronic device obtained through an undercover operation, a move that has reignited long-standing questions about the cause of Havana Syndrome, the mysterious illness that has affected American diplomats, intelligence officers, and military personnel worldwide. According to multiple officials briefed on the matter, the device was purchased for eight figures, meaning tens of millions of dollars, using Defense Department funds and acquired through Homeland Security Investigations (HSI) during the final months of the Biden administration.

The device emits pulsed radiofrequency energy, a technology that scientists and intelligence analysts have debated for nearly a decade as a possible explanation for the unexplained neurological symptoms linked to Havana Syndrome, officially termed Anomalous Health Incidents (AHIs). Some investigators believe the device may replicate or approximate the effects reported by victims, though the link remains unproven and controversial inside the US government.

The testing has taken place amid growing global instability. Rising tensions involving Iran, Israel, Russia, and the United States have increased concern within national security circles that unconventional and deniable technologies could be used to harm personnel without triggering open conflict. While US intelligence agencies still assess it as very unlikely that Havana Syndrome resulted from a coordinated foreign attack, the existence of a portable, high-energy device capable of neurological impact has sharpened internal debate.

Inside the undercover operation and the device under review

HSI, a powerful investigative arm of the Department of Homeland Security, acquired the device using Defense Department funding, according to officials familiar with the operation. The purchase was conducted discreetly and involved international elements. While the device is not entirely Russian in origin, investigators confirmed it contains Russian-manufactured components, adding to existing suspicion surrounding Moscow’s advanced electromagnetic research programs.

Officials described the device as compact and mobile, potentially small enough to fit into a backpack. That detail is significant. One of the biggest unresolved questions surrounding Havana Syndrome has been whether a weapon powerful enough to cause brain-like injuries could realistically be portable. The device under study suggests that such mobility may be technically possible.

The Pentagon has not publicly disclosed where the device was obtained or from whom. That secrecy is consistent with HSI’s role in investigating technology proliferation, particularly when US-controlled or sensitive technologies surface in conflict zones or foreign markets. Historically, the US military has relied on HSI to trace how advanced equipment moves across borders, including in war zones such as Iraq and Afghanistan.

What is Havana Syndrome?

Havana Syndrome first emerged in late 2016, when US diplomats stationed in Havana reported sudden symptoms including dizziness, severe headaches, nausea, cognitive impairment, and balance problems. Over time, similar cases were reported in Europe, Asia, and the Middle East, affecting CIA officers, State Department staff, and military personnel.

Medical investigations have been complicated by inconsistent reporting timelines and the absence of a universally accepted definition of AHIs. In many cases, medical tests were conducted months or years after symptoms began, limiting diagnostic certainty. Still, in 2022, an expert intelligence panel concluded that some cases could “plausibly” have been caused by pulsed electromagnetic energy from an external source.

Despite that finding, the intelligence community stated in 2023 that it could not link any known cases to a foreign adversary. That position was reaffirmed as recently as January 2025, when analysts again said a hostile campaign was very unlikely, while acknowledging that a small number of cases remain unexplained.

Intelligence skepticism, victims’ anger, and congressional scrutiny

The Pentagon’s testing of the device has reopened wounds among Havana Syndrome victims, many of whom believe the US government dismissed credible evidence for years. Several affected officers were forced into early retirement due to lasting neurological damage.

Marc Polymeropoulos, a former CIA officer who reported symptoms after an alleged incident in Moscow in 2017, called the discovery of such devices potential vindication. He and others argue that intelligence agencies minimized the threat to avoid diplomatic fallout, particularly with Russia.

Congress has taken the issue seriously. Defense officials briefed the House and Senate Intelligence Committees late last year, discussing both the device and the broader implications of directed-energy technologies. Lawmakers were reportedly concerned about proliferation risks, especially as geopolitical flashpoints intensify.

In the context of escalating tensions involving Iran and Israel, as well as US military deployments across the Middle East, officials worry that emerging technologies could be used covertly against American personnel without triggering traditional military responses. The concern is not limited to one country. If the technology is viable, multiple states or non-state actors could eventually obtain it.

What the testing means for US security policy

The Pentagon, DHS, and CIA have declined to comment publicly. Still, the continued testing signals that the US government has not fully closed the door on the directed-energy hypothesis. The goal now appears to be understanding capability, limits, and replication, rather than assigning blame.

For policymakers, the issue extends beyond Havana Syndrome. It raises urgent questions about force protection, medical readiness, and the evolving nature of low-visibility threats. As global rivalries deepen and unconventional tools become more accessible, the challenge for US defense planners is preparing for attacks that leave no obvious fingerprints.

For now, Havana Syndrome remains officially unexplained. But the undercover acquisition of a powerful, portable energy-emitting device suggests the mystery is far from settled—and that the next phase of investigation may reshape how the US understands invisible threats to its people abroad.

FAQs:

Q: What is the device the Pentagon tested, and why is it significant to the Havana Syndrome investigation?

A: The device emits pulsed radiofrequency energy and was purchased in an undercover operation for an eight-figure sum. It is compact enough to be portable, addressing long-standing doubts about feasibility. Officials are testing whether it could replicate symptoms reported since 2016. No definitive causal link has been confirmed.

Q: Has the US intelligence community concluded that Havana Syndrome was caused by a foreign attack?

A: As of January 2025, US intelligence agencies assess it as very unlikely that a coordinated foreign campaign caused the incidents. However, analysts have not ruled out external involvement in a limited number of cases. Congressional briefings continue as testing of the device remains ongoing.