JERUSALEM — American officials said on Wednesday that they were investigating the killing of three United States soldiers at a Jordanian air base this month as a possible terrorist attack and dismissed suggestions that the three had done anything to provoke the shooting.
The Nov. 4 shooting has been shrouded in secrecy as American and Jordanian officials investigate, a sign of the sensitivity surrounding the episode. But the Americans evidently became irritated at reports that seemed to place at least some blame on the soldiers.
“Investigators are considering all potential motives and reasons for why American service members came under fire and they have not yet ruled out terrorism as a potential motive,” the American Embassy in Jordan said in a statement. “Contrary to press reports, there has been absolutely no credible evidence to suggest that U.S. personnel acted contrary to orders or established procedures when accessing the base.”
The three soldiers, all with the Special Forces, were in Jordan on a training mission and were returning to the air base in the southern desert when a Jordanian soldier opened fire on them. The Jordanian soldier was wounded in what was described as an exchange of fire, and is in custody.
Jordanian officials initially said the American soldiers failed to heed orders to stop as they approached the base gate. A subsequent report in The Washington Post, citing Jordanian accounts, said the episode began with the accidental discharge of a weapon inside one of the vehicles carrying the Americans, who it said were part of a C.I.A. program to train Syrian rebels.
While American military officials confirmed that the soldiers were part of the C.I.A. program — though a C.I.A. spokesman declined to comment on the episode — the report angered the American side, which saw it as an attempt by Jordan’s government to shift blame.
Several American military officials said the only real question about what happened was the motive of the gunman.
Initial classified assessments of the shooting could be seen to support either the idea that the gunman was a jihadist or that it was some sort of accident, according to the military officials, who spoke on the condition of anonymity to discuss an ongoing investigation.
Some of the officials said they feared that Jordan would try to blur any conclusion that the gunman had been motivated by radical religious beliefs, out of reluctance to discuss any problem with extremists in the security forces.
To sort through that, a team of F.B.I. agents from Washington was sent to Jordan. Video surveillance captured the episode, officials said, but there was no audio and it was not clear if everything relevant occurred within the camera range.
The three soldiers were identified as Staff Sgts. James F. Moriarty, 27, Matthew C. Lewellen, 27, and Kevin J. McEnroe, 30, all from the 5th Special Forces Group (Airborne) based at Fort Campbell, Ky.
Sergeant Moriarty’s father, James R. Moriarty, a Houston lawyer, said he spoke at length with a fourth American soldier who was present and survived the shooting. That soldier said the Jordanian soldier opened fire without provocation, Mr. Moriarty said.
The four soldiers had been at a training exercise at a shooting range outside the King Faisal Air Base near Al Jafr. One of the munitions failed to go off, so while the rest of the training team headed back to base, Sergeant Moriarty and three others stayed behind to detonate it safely, according to the account told to his father.
The four then headed back to the base in multiple vehicles, none of them wearing body armor or armed with rifles because it was assumed to be safe. The base has a double barrier entrance: Entering vehicles can be searched after passing the first barrier before being permitted past the second. Sergeant Moriarty and his colleagues were allowed past the first barrier but not the second, his father said.
“The kids were trapped and they were trapped in a safe zone,” Mr. Moriarty said. “Lord knows how many times they had gone through that gate before and they had clearly trusted the Jordanians to at least not start murdering them.”
According to the account Mr. Moriarty cited, a Jordanian soldier fired on the Americans with a semiautomatic rifle. He gunned down two of the soldiers right away, and Sergeant Moriarty and the surviving soldier left their vehicles. When the Jordanian continued firing, they ducked behind jersey barriers and returned fire with their pistols. The surviving soldier hit and wounded the Jordanian, but the other three Americans died.
“It’s clear to me that was an assassination,” Mr. Moriarty said. “The shooter was wearing body armor. He’s carrying an AK-47. He makes the choice not to drop the rolling metal barrier, which was the final barrier before you get on the base.”
“This guy’s obvious intent was to kill those four Americans,” he added, “and he did everything he possibly could to do that. That doesn’t fly with any other explanation.”
American and Jordanian officials declined to comment publicly beyond the embassy statement, saying the investigation was ongoing.
Even as the Americans disputed the Jordanian account, they sought to avoid a rupture. “We appreciate the assistance of the government of Jordan as the investigation continues,” the embassy statement said.