The US military is investigating reports that some its troops this week refused to take part in a supply convoy in Iraq, on a route where explosive devices have killed dozens of soldiers.
A statement issued by the US military press centre in Baghdad called it an "isolated incident."
The brief communiqué said some members of the 343rd Quartermaster Company, a unit that moves water and other supplies for American troops, reportedly refused to participate in their assigned convoy mission on Wednesday.
Refusal to obey orders, especially in a combat zone, is a serious offence. But the statement stressed that "it is far too early in the investigation to speculate as to what happened, why it happened or any action that might be taken."
Family members of some of the 17 troops told a US newspaper that security for the fuel trucks was inadequate.
The Clarion-Ledger
Civilian and military convoys in Iraq, where more than 1,000 US troops have been killed since the US-led invasion in March 2003, are frequently targets for roadside bombings and other ambushes.
"I got a call from an officer in another unit early (Thursday) morning who told me that my husband and his platoon had been arrested on a bogus charge because they refused to go on a suicide mission," the newspaper quoted Ms Jackie Butler of Jackson.
"When my husband refuses to follow an order, it has to be something major," she said of Sgt Michael Butler, a 24-year reservist.
The military said the commanding general of the 13th Corps support command had appointed the deputy commander to lead an investigation of the allegations.
"It is important to note that the mission in question was carried out using other soldiers from the unit," the statement said.
"The investigating team is currently in Tallil taking statements and interviewing those involved," it added.
in Jackson, Mississippi, reported that interviews with some family members indicated soldiers from the unit based in Tallil refused to go on the mission because they did not have an adequate armed escort and the vehicles were not in good shape.