The briefings included information about injuries sustained by U.S. troops in Syria, the people said. The investigation includes one incident in Syria in the fall of 2020 in which several troops developed flu-like symptoms, two people familiar with the Pentagon probe said. A Pentagon spokesperson, however, said the department is not aware of directed-energy attacks against U.S. troops in Syria. The spokesperson declined further comment on the Pentagon’s interactions with Capitol Hill or any internal investigation. The incidents of suspected directed-energy attacks by Russia on Americans abroad became so concerning that the Pentagon’s office of special operations and low-intensity conflict began investigating last year, according to two former national security officials involved in the effort. It’s unclear exactly how many troops were injured, or the extent of their injuries.