(Adds details from local TV reports)
By Jon Herskovitz
AUSTIN, Texas, April 2 (Reuters) - At least one gunman opened fire at Fort Hood on Wednesday, injuring an unknown number of people at the U.S. Army base in central Texas that was the scene of a shooting rampage in 2009, officials said.
The base said in a statement that its directorate of emergency services "has an initial report that a shooter is dead, but this is unconfirmed."
It added: "the number of injured are not confirmed at this time."
Local news reports said there may be two suspected shooters, while CNN reported that one shooter was believed to be dead, citing a U.S. official.
NBC reported that 8 people were wounded in the shooting, 4 of them critically.
News of the shooting, the third such incident at a military base in the United States in about six months, was being relayed to President Barack Obama, the White House said.
"The president has been informed of reports of a shooting at Fort Hood. He'll continue to receive updates on the situation throughout the evening," White House spokesman Josh Earnest told reporters.
The base has been put on lockdown and police were securing its perimeter, police and military officials said. Helicopters could be seen circling the base in live TV footage broadcast from the scene.
A video from Fort Hood broadcast on local TV station KCEN TV showed a loud announcement going through the base telling people to lock their windows and doors.
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 canceled classes.
In 2009, a former Army psychiatrist shot dead 13 people and wounded 32 others in a shooting spree at Fort Hood.
In September, a gunman opened fire at the Washington Navy Yard, killing 12 and wounding 4 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 and Caren Bohan in Washington, editing by Gunna Dickson and G Crosse)