Fort Hood hash tweet stream is here.
It's possibly too soon to say this, but the NRA argument that if everyone is armed, everyone is safe, is pretty much belied by the fact this incident at an army base.
UPDATE: 2 to 3 suspected shooters involved, reportedly wearing U.S. Army uniforms (although this doesn't mean they are U.S. soldiers). One suspect possibly still at large.
UPDATE (4:10 pm): Well, with the caveat that there is confusion and (probably) some error in the news reports, one first thought is that this might be a couple of oathkeepers. Or some terrorist attack. Since there were three two suspects, one can almost rule out the lone mentally deranged PTSD guy.
Latest reports say only two shooters, both caught, but some SWAT people are wounded.
UPDATE (4:30 pm): Some reports saying 9 dead, up to 30 wounded. Also scattered reports of another shooting at an Army residence, and it is unclear whether the base is secure yet.
UPDATE (4:50 pm): Local Tx affiliate says one of the apprehended suspects is a military officer, an Army major. CNN now reporting 12 dead, including one gunman.
Army spokesman just confirmed 12 dead, 31 wounded. Shooter was killed; two other suspects arrested — ALL of them US soldiers.
UPDATE (5:00 pm): Shooter was Army major "with Arabic-sounding name", MSNBC reports.