By Jon Herskovitz
AUSTIN, Texas (Reuters) - Several people were killed and at least 14 injured on Wednesday when a gunman opened fire at a U.S. Army base in Fort Hood, Texas, the site of another rampage in 2009, U.S. officials said.
One official, who spoke on the condition of anonymity, declined to offer specific numbers on fatalities. A separate U.S. official, also speaking on condition of anonymity, said 14 people had been injured.
He noted the information was preliminary and said he could not confirm reports the shooter had been killed. Local news reports said there may be as many as four dead, although this could not be confirmed.
The base said in a statement that its directorate of emergency services "has an initial report that a shooter is dead," but also added that the information was unconfirmed.
It said: "The number of injured are not confirmed at this time."
The Scott and White Hospital in Temple, Texas, said it had received four patients, ranging from critical condition to stable with single and multiple gunshot wounds. Two more were arriving soon, hospital officials told a news conference.
U.S. President Barack Obama said he was "heartbroken" that another shooting had occurred at the Fort Hood Army base and described the situation there as fluid.
"We are going to get to the bottom of exactly what happened," Obama told reporters in Chicago, where he is travelling for Democratic fundraisers. "We're heartbroken that something like this might have happened again."
Defense Secretary Chuck Hagel told a news conference in Honolulu, where he was meeting with Asian defense ministers the incident was still under investigation.
"It's a terrible tragedy. We know that. We know there are casualties, both people killed and injured," he said.
After the shooting, the third such incident at a military base in the United States in about six months, Fort Hood was put on lockdown and police were securing its perimeter, military officials said. Helicopters could be seen circling the base in live TV footage broadcast from the scene.
An announcement telling people to lock their windows and doors can be heard on a video from Fort Hood broadcast on local TV station KCEN.
Police went from building to building, while scores of police vehicles and ambulances were on the scene, the station said.
Authorities advised those on the post to stay away from windows and to keep doors closed and locked.
Central Texas College, which has a Fort Hood campus, ordered an immediate evacuation of all students and staff, and cancelled classes.
In 2009, a former Army psychiatrist shot dead 13 people and wounded 32 others in a shooting spree at Fort Hood.
Major Nidal Hasan shouted "Allahu Akbar," or "God is greatest" in Arabic, during the attack and later said he wanted to be a martyr. He was convicted and faces death by lethal injection
In September, a gunman opened fire at the Washington Navy Yard, killing 12 and wounding four before being slain by police. Last month, a civilian shot dead a sailor aboard a ship at a U.S. Navy base in Norfolk, Virginia.
(Additional reporting by Lisa Maria Garza in Dallas, Jeff Mason in Chicago, David Alexander and Caren Bohan in Washington, and Phil Stewart in Honolulu; Editing by Gunna Dickson, G Crosse and Lisa Shumaker)