Fort Hood's official Twitter feed asked that all personnel on post shelter in place. Sirens blared.
The lockdown at the Army installation was lifted just prior to 9 p.m. (10 p.m. ET), military personnel at the front gate told CNN.
On November 5, 2009, Army Maj. Nidal Malik Hasan opened fire at Fort Hood, killing 13 people and injuring 32.
He shot fellow soldiers at the processing center. Prosecutors maintained that the American-born Muslim underwent a progressive radicalization that led to the massacre.
Hasan allegedly picked that day because it was when the units he was scheduled to deploy with to Afghanistan were scheduled to go through the processing center.
The former Army psychiatrist was convicted of premeditated murder, and a military jury recommended that Hasan be put to death.
Wednesday's shooting reminded many in the central Texas community of that incident.
"Today, Ft. Hood was once again stricken by tragedy. As Texans, our first priority must be caring for the victims and their families. Ft. Hood has proven its resilience before, and will again. Texas will support those efforts in any way we can, with any resources necessary," said Gov. Rick Perry.
U.S. Sen. John Cornyn said in a statement that no community should have to experience such violence once, let alone twice.
"Tonight, Texans' hearts are once again very heavy. The scenes coming from Fort Hood today are sadly too familiar and still too fresh in our memories," he said.
According to the Fort Hood website, the post is one of the largest in the world with 45,414 assigned soldiers and 8,900 civilian employees.
The installation, which encompasses 214,000 acres, is home to two divisions -- the Army's 1st Calvary and the 4th Infantry (Mechanized). There are 12 other units attached or based there.
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