By Bill Rigby

TACOMA, Washington (Reuters) - An Afghan villager and two of his sons, who survived a night-time shooting rampage in March, testified on Saturday that they saw only one U.S. soldier attacking their compound, backing the U.S. government's account.

Military prosecutors are seeking the death penalty for Army Staff Sergeant Robert Bales, accusing him of killing 16 villagers, mostly women and children, when he ventured out of his remote camp on two revenge-fueled forays over a five-hour period in March.

The shootings in Afghanistan's Kandahar province marked the worst case of civilian slaughter blamed on an individual U.S. soldier since the Vietnam War and damaged already strained U.S.-Afghan relations.

The U.S. government says a coherent and lucid Bales acted alone and with "chilling premeditation".

Some villagers told reporters shortly after the attacks that more than one U.S. soldier was involved, but there have been no sworn statements to that effect made publicly.

Early on Saturday, three survivors answered questions via video-link from Kandahar Air Field to a hearing at a U.S. Army base in Washington state - the first time Afghan witnesses have testified under oath about what transpired on March 11.

"He shot me right here," said Haji Mohamed Naim, the father of nine sons in the village of Alkozai, the scene of the first shootings.

Speaking through an interpreter, he said all he could see was a strong light on the head of a soldier who was not more than half a meter (yard) away from him when he started shooting.

Naim said he was awoken in the night by sounds of shots and dogs barking, and then children from the next door house knocked on his door. He then described how an "American" jumped from a wall before confronting him and starting to shoot.

Two of Naim's sons, who were also in the compound, said they saw only one U.S. soldier on the night in question.

"Yes, I saw him, he came after me, I went to another room," said Naim's son Sadiquallah, who said he was 13 or 14 years old. He described how he hid behind a curtain in a storage room with one other child, and was hit in the ear with a bullet, but did not see who fired the shot.

"How many Americans did you see?" one of the prosecution attorneys asked Sadiquallah. "One," he replied.

His older brother Quadratullah, who said he was 14, was unscathed in the attack, but said he saw a U.S. soldier shooting other children.

"Yes I saw the American," he answered a government attorney. "I said 'We are children, we are children', and he shot one of the kids," Quadratullah said, through an interpreter.

"We saw only one American," he added.

At a courtroom at the Joint Base Lewis-McChord, Bales sat impassively throughout the proceedings, watching the witnesses on a TV screen in front of him.

FIRST AFGHAN TESTIMONY

The Afghan villagers testified on the fifth day of a hearing to establish whether there is enough evidence to put Bales before a court martial.

A veteran of four combat tours in Iraq and Afghanistan, Bales faces 16 counts of premeditated murder and six counts of attempted murder, as well as charges of assault and wrongfully possessing and using steroids and alcohol while deployed.

Prosecutors have presented physical evidence to tie Bales to the crime scene, with a forensic investigator saying a sample of blood on Bales' clothes matched a swab taken in one of the compounds where the shooting occurred.

Bales' lawyers have not set out an alternative theory, but have pointed up inconsistencies in testimony and highlighted incidents before the shooting where Bales lost his temper easily or appeared unbalanced, possibly setting up an argument that he was suffering from post-traumatic stress disorder.

Gathering evidence and witness statements was complicated by the speedy burial of victims, the inability of U.S. investigators to access the crime scenes for three weeks after the violence for fears of revenge attacks, and the dispersal of possible witnesses after treatment at a Kandahar hospital.

Bales' lead civil defense attorney John Henry Browne, who is in Kandahar to question the witnesses, complained early in the investigation that his team was denied access to villagers wounded in the attacks.

(Reporting by Bill Rigby; Editing by Cynthia Johnston and Alistair Lyon)