The committee chairman, Rep. Michael McCaul, R-Texas, told CNN he had been briefed on the deadly incident and said there were also 14 injuries. Authorities were concerned another shooter might be at large, but no link to terrorism has been discovered, the lawmaker said.
Before McCaul's appearance on CNN, Fort Hood's media office cited an initial report that the shooter was dead but said the report was not confirmed.
Sgt. Maj. Nicholas Connor, a spokesman for Fort Hood, told ABC News that authorities would lift a "shelter in place" order as soon as they believed it was safe to do so.
President Obama said his national security team was "working with folks on the ground to determine exactly what happened and to ensure that everyone is secure."
"The situation is fluid right now. ... Any shooting is troubling," the president said. "We're heartbroken that something like this might have happened again. I don't what on the comment on facts until we know exactly what happened. But just for now I would hope that everyone across the country keep the families of Fort Hood in our thoughts and our prayers. ... We don't yet know what happened tonight but obviously that sense of safety has been broken once again."
Connor said, "Unfortunately, this is something that we here at Fort Hood have experience with and this is something that is conjuring up a lot of memories of the past.
Fort Hood, in Killeen, Texas, was the site of a mass shooting in 2009, when Army psychiatrist Maj. Nidal Hasan killed 13 people.
During Hasan's trial, he called himself a "mujahedeen," or Muslim holy warrior, and did not deny he was the shooter. He was convicted and received the death penalty in August 2013.