The New York Times quoted administration officials saying on Saturday US Central Command was prepared to release the Syrians on Tuesday, but civilians at the Pentagon wanted them questioned more extensively to absolve them of any role in assisting the Iraqi convoy.
A Pentagon spokesman, Larry Di Rita, said on Friday he did not know when repatriation would take place, or why it was taking as long as it was and that it was largely in the hands of the US Embassy in Damascus.
The US raid was launched on 18 June because of intelligence suggesting the convoy was carrying senior members of Iraq's deposed Baathist regime.
Neither the United States nor Syria has made clear whether the incident took place on Syrian soil.
Di Rita would not say how the Syrians were injured, or whether US troops crossed into Syrian territory during the attack on the convoy in western Iraq.
The delay came amid objections from Syria, US military officers on the ground and the US State Department, which feared it would harm relations with Damascus, the New York Times said.
Harming strained ties
Syrian-US relations have been tense over recent months over American allegations that Damascus has helped members of the former Iraqi government flee and that it was developing chemical weapons.
Syria denies the charges.
On Wednesday, the Syrian Arab News Agency said Syria had demanded the US should "return ... the wounded soldiers to continue their treatment at a Syrian hospital to avoid any misunderstanding that might lead to an escalation that both sides do not desire".
Di Rita said the five were taken into US custody to be treated for various types of injuries. Three were taken to Baghdad and the other two were treated by a US military unit in the area, he told reporters.
"All five are now together, have been treated, are ambulatory and are awaiting their return," he said.
Di Rita said an unidentified Iraqi was killed in the raid, adding he did not know whether the Syrians had been part of the targeted convoy or assisting it in some way.
"They've only been able to confirm one individual was killed, but that doesn't mean that only one individual was killed," he said.