UPDATE, April 3 at 9:00a ET: The gunman has been identified as Spc. Ivan Lopez, an Iraq War veteran being treated for mental illness, authorities say. Get more details here.

UPDATE, 11:01p ET: At a news conference, Army Lt. Gen. Mark Milley said four people, including the shooter, have died. Another 16 were hurt and are being treated. He said the shooter suffered from mental health issues and died of a self-inflicted gunshot wound. Read more about the conference here.

UPDATE, 9:16p ET: Officials from Baylor Scott & White Health Central Texas held a news conference to update the media on those injured in the Fort Hood shooting today. Watch it here.

UPDATE, 8:38p ET: President Barack Obama delivered a statement on the Fort Hood shooting. Watch it here.

UPDATE, 8:17p ET: Senior U.S. officials confirm to Fox News that the shooter was Spc. Ivan Lopez. He is believed to have taken his own life.

UPDATE, 8p ET: Shepard Smith reported that four people are dead, including the shooter, at Ford Hood. Another 14 are injured.

UPDATE, 7:33p ET: Fox News has confirmed from its sources that one person has died and 14 more are injured. It is believed that the shooter is dead.

UPDATE, 7:15p ET: Shepard Smith reported that according to Fox News sources, preliminary sources indicate this may be "soldier on soldier." This has not been confirmed.

UPDATE, 7:08p ET: Greta Van Susteren reported that one person may be dead. 

UPDATE, 6:59p ET: The threat from one shooter has been neutralized, a senior law enforcement official tells Fox News. There is the possibility of another shooter. At least two victims have been taken to the hospital, and there may be more. Nearby Central Texas College has been evacuated. 

President Obama has been briefed on the situation.

UPDATE, 6:24p ET: A Fox News producer who spoke to someone on the military post reports this is an active shooter situation and two victims have come into the ER so far. 

UPDATE, 6:17p ET: The Texas Department of Public Safety says there are casualties but cannot say how many at this time. Jennifer Griffin reported that people have been told to shelter in place. 

The FBI tells Fox News that police are en route to the scene and bureau agents are headed there from Waco. It’s unclear whether there’s an active shooter scene. The military post may be locked down at this time.

In 2009, a shooter gunned down 13 people at Fort Hood. Army psychologist, Maj. Nidal Hasan, was sentenced to death last year for those murders. Hasan was also found guilty of 32 attempts of premeditated murder. 

Stay tuned for details on this breaking news story.