FORT HOOD, Texas - All-clear sirens have sounded and the lockdown has been lifted at Fort Hood after a gunman opened fire at the Texas Army post, killing three people and wounding several others before taking his own life, law enforcement sources told CBS News.
Those same sources said four people were dead, including the gunman, who died of a self-inflicted wound.
Several others were wounded, and while the exact number was not immediately clear, initial reports said as many as 14 people with injuries.
CBS News sources have identified the suspect as 34-year-old soldier Ivan Lopez, and said the violence apparently stemmed from some sort of soldier dispute. Texas Rep. Michael McCaul, chairman of the House Homeland Security Committee, also identified the shooter as Lopez.
The shooting reportedly began around 4:25 p.m. near the transportation motor pool.
A soldier at the base told our Gannett partner, KENS-TV, that about 20 rounds were shot outside before Lopez went into the medical brigade building. The soldier added there appeared to be some sort of standoff happening.
"Immediately [I] heard four gun shots and assumed they were blank rounds," the soldier said. "We then heard a burst, another burst and it was clear they weren't blank rounds. They were live rounds."
The solider, who said he saw at least one person get hit, told KENS-TV he watched a soldier jump over a fence and run away, but it was not clear whether that individual was the shooter.
Fort Hood ordered everyone at the Texas Army base to "shelter in place". The order was sent on the base's Twitter and Facebook accounts.
The 1st Calvary Division, which is based at Fort Hood, also sent a Twitter alert telling people on base to close doors and stay away from windows.
The shooting and reported injuries were confirmed a short time later through another 1st Calvary Division tweet.
Emergency crews from several surrounding communities headed to the base.
According to CBS News, word from Baylor Scott & White Health officials Wednesday evening indicated the hospital was treating four patients and that others were en route. The patients had injuries to the chest, neck and extremities, and their conditions ranged from stable to quite critical.
According to White House spokesman Josh Earnest, President Obama was informed of the shooting while in Chicago.
"We're heartbroken something like this might have happened again,'' the President said, referring to the 2009 mass shooting at Fort hood that killed 13 people, and wounded more than 30. It was the deadliest attack on a domestic military installation in history.
Navy Rear Admiral John Kirby said Defense Secretary Chuck Hagel was also informed.
Metroplex Hospital in Killeen was placed on standby, and Central Texas College was evacuating and canceling Wednesday night classes in response to the Fort Hood developments.
A spokeswoman for the base declined to comment, and a spokesman for the local sheriff's office did not immediately have information on the incident.
Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, offered sympathies to the Fort Hood community on Wednesday night.
"Our thoughts and prayers are with the Fort Hood community in the aftermath of this tragedy. Many questions remain and our focus is on supporting the victims and their families," Dempsey said. "This is a community that has faced and overcome crises with resilience and strength."