(Adds more testimony)
By Karen Brooks and Lisa Maria Garza
FORT HOOD, Texas, Aug 8 (Reuters) - One after another, U.S. Army soldiers described panic and chaos, smelling smoke and blood and feces, feeling the sharp pain of bullets tearing through their backs, legs, shoulders and arms.
A pregnant woman cried out "my baby! my baby!" before being shot dead.
They were not in the wars in Iraq or Afghanistan, but on the Fort Hood military base in Texas on Nov. 5, 2009, when one of their own, Army psychiatrist Major Nidal Hasan, opened fire on anyone in uniform, witnesses testified at Hasan's court-martial on Thursday.
They recalled playing dead in order to escape more harm and making futile efforts to save their friends. The soldiers were unable to fire back because they are prohibited from carrying weapons on base. Military police eventually shot Hasan, who was paralyzed from the waist down and attends court in a wheelchair.
"There were a lot of bodies on the ground. The chairs were overturned, a lot of blood on the floor. It smelled like gunpowder, feces, blood. Pretty bad," said Staff Sergeant Michael Davis, who thought the gunfire was a drill until "I saw somebody get hit, I saw a blood spray."
Hasan, a U.S.-born Muslim, admitted to the jury on the opening day of testimony on Tuesday that "I am the shooter," saying he had "switched sides" in what he called a U.S. war on Islam.
In the shooting rampage days before Hasan was to be deployed to Afghanistan, he killed 13 and wounded 31 at the Soldier Readiness Processing Center on the base.
Prosecutors opted against bringing terrorism charges but Hasan could still face the death penalty if all 13 officers on the jury find him guilty of premeditated murder, possibly making him the first service member executed by the U.S. military since 1961.
Earlier on Thursday, Judge Colonel Tara Osborn denied a request by Hasan's standby lawyers to reduce their role, ordering them to continue assisting Hasan in defending himself.
The three lawyers said Hasan was actively seeking the death penalty - an assertion disputed by Hasan - and they objected to playing a role in such an outcome.
Osborn turned the defense lawyers down, saying the U.S. Constitution allowed Hasan the right to defend himself and calling the rift "nothing more than their disagreement with Major Hasan's trial strategy."
Among the 12 eyewitnesses to testify was Private Lance Aviles, who recalled seeing his friend, Private First Class Kham Xiong, being shot dead just moments after chatting about the New York Yankees' recent victory in the World Series.
"I see my buddy hit the floor. He had an exit wound from the back of his skull, and blood on my boots," Aviles said.
Sergeant Maria Guerra recalled a woman crying "Please don't! Please don't! My baby! My baby!" as the shooting began.
Private Francheska Velez, six weeks pregnant, was shot in the back as she pleaded for her unborn child's life, prosecutors said in opening statements.
"He was firing into the crowd of soldiers," Guerra said, choking back tears. "As he's firing, he's very efficiently dropping his magazine and coming up with another magazine." (Additional reporting by Jana J. Pruet; Writing by Daniel Trotta; Editing by Richard Chang)