This story is published in a content partnership with POLITICO. It was originally reported by Lara Seligman, Andrew Desiderio and Erin Banco on politico.com on April 29. US officials are investigating a suspected directed-energy attack on federal government personnel in Miami last year, as well as at least two other incidents involving US officials on American soil, according to people familiar with the investigation. In Miami, several people reported symptoms similar to those exhibited by American spies and diplomats in Cuba starting in 2016 that became known as “Havana syndrome”, three people said. It was unclear which agency the people in the Miami incident belonged to. Officials are also investigating two similar incidents – one last year involving a senior National Security Council official walking to his car from the south lawn of the White House known as the Ellipse, and another in 2019 involving a separate NSC official walking a dog in Alexandria, Virginia, the people said. The effort is part of a broader investigation into suspected directed-energy attacks against Americans around the world, which became so alarming to US officials that the Pentagon began a probe last year. The attacks, which have caused varying symptoms including brain damage, are difficult to track and attribute with confidence due to their nature. The devices involved can be small and portable, and the symptoms can appear similar to other illnesses. Representatives for the NSC, FBI and Office of the Director of National Intelligence declined to comment. Officials across the US government have investigated these and other similar suspected directed-energy attacks, including possible targeting of US service members at home and abroad, and have sounded the alarm about the issue to lawmakers, POLITICO first reported . The incidents involved officials working for both the Pentagon and the CIA. CNN on Thursday first reported the incident on the Ellipse. GQ reported on a similar incident in Arlington last year. US troops increasingly vulnerable to directed-energy attacks, Pentagon warns Two Pentagon officials briefed members of the House Armed Services Committee about the suspected attacks in a classified setting last week, POLITICO first reported . The briefers were Jennifer Walsh, the then-acting Pentagon policy chief; and Griffin Decker, the Pentagon’s director of the emerging threats cell. Officials have told lawmakers that they believe the threat of directed-energy attacks around the world is growing. The briefers said suspected directed-energy attacks have occurred on US soil, including the suspected Ellipse and Alexandria incidents, according to a person familiar with the discussions. They did not make a formal determination on whether the incidents amounted to directed-energy attacks. Briefers also did not say conclusively who was responsible for the suspected attacks, but identified both Russia and China as likely suspects. In a separate recent briefing in Europe that included State and Pentagon officials, a defence official said there has been an increasing number of directed-energy attacks on US troops reported worldwide, including in Europe and the US, a senior official with direct knowledge of the matter told POLITICO. Lawmakers are already pressing top Biden administration officials to disclose more information to the public. During a Senate Armed Services Committee hearing Thursday morning, Senator Jeanne Shaheen pressed Director of National Intelligence Avril Haines on what the New Hampshire Democrat referred to as a “clamp-down” on information about the suspected directed-energy attacks, noting that “there has been a real effort to try and keep this information classified”. Shaheen urged Haines to be more transparent with lawmakers about the suspected attacks as well as the ongoing investigations. “The horse is out of the barn on this. The information is already out there,” Shaheen said. “And I think it behoves us all to try and make sure the information that gets out is accurate, and that people understand what’s happening and that there is an effort to respond to that.” Shaheen later told POLITICO that she followed up with Haines about the matter in a classified setting and still believes that more information about the suspected attacks should be declassified. In testimony before the Senate Intelligence Committee this month, Haines did reference “anomalous health incidents that have affected a number of our personnel”. “The Intelligence Community is taking these incidents very seriously, and is committed to investigating the source of these incidents, preventing them from continuing, and caring for those affected,” Haines said. “We appreciate the support that many of you have shown for our personnel on this issue, as with everything else we work on around the globe.” Betsy Woodruff Swan contributed to this report. Read Politico’s story .