ABC -- The chairman of the House Homeland Security Committee said four people were killed, including the gunman, and 14 were injured in a shooting incident today at Fort Hood in Texas.
Rep. Michael McCaul, R-Texas, told CNN he had been briefed on the deadly incident and said authorities were concerned another shooter might be at large. So far, no nexus 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 the "shelter in place" order as soon as they believed it was safe to do so.
Scott and White Hospital in nearby Temple, Texas, said it activated its internal incident management system and "is receiving patients" related to the shooting.
President Obama and Secretary of Defense Chuck Hagel have been informed of the shooting, according to their spokespeople.
"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," Connor said. "We're just hoping we can get to the bottom of this as soon as possible."
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.