A platoon of Army reservists in Iraq is being investigated for allegedly refusing to carry out a convoy mission its members deemed too dangerous, Army officials said yesterday.

On Wednesday, 19 soldiers from the 343rd Quartermaster Company failed to report for a planned fuel convoy from Tallil Air Base across central Iraq to Taji, a base north of Baghdad, the Army said in a statement issued in Iraq. The unit is headquartered in Rock Hill, S.C., but is currently based in Tallil.

"An initial report indicated that some of the 19 soldiers (not all) refused to participate in the convoy as directed," the Army statement said. Brig. Gen. James E. Chambers, commander of the Army's 13th Corps Support Command, to which the reserve unit is attached, has ordered an investigation that is now underway, the statement said.

The soldiers were concerned about the roadworthiness of their trucks and the lack of a helicopter escort for the mission, according to Rep. Bennie Thompson (D-Miss.), who said he had talked with the wives of two of them who live in his district.

The Army statement called the incident "a temporary breakdown in discipline."

"This is an isolated incident, and it is far too early in the investigation to speculate as to what happened, why it happened or any action that might be taken," the statement continued. It also noted: "The 343rd is an experienced company that has performed honorable service for nearly nine months in Iraq."

The incident is the latest indication of troubled morale in some National Guard and reserve units called up for Iraq duty. Last month, several hundred soldiers of a National Guard unit, also from South Carolina, were locked down in their barracks at Fort Dix, N.J., where they had been training before deploying to Iraq for a year of convoy escort duty. That action was taken after 13 members of the unit went AWOL, mainly to see their families before shipping out; after several soldiers were involved in a brawl; and after other indications of indiscipline.

Relatives of soldiers in the 343rd Quartermaster Company told the Clarion-Ledger in Jackson, Miss., that members of the unit had been placed under arrest and moved from their barracks to tents. But a spokesman for the 13th Corps Support Command said that report is incorrect.

"No soldiers are being held, and no soldiers are currently under arrest," Maj. Richard Spiegel said from Iraq. He said there had been some confusion on that point because "the command did relocate some of those involved to different living quarters, but they were not restricted or guarded in any way."

Spiegel said it is not yet clear whether there will be any legal action against the soldiers. He also said it appears that "far less than 19" soldiers were "involved in any alleged actual refusal to perform a mission."

Thompson said the wives of two of the soldiers told him the men were detained, along with 15 others.

Thompson added that he has asked the Pentagon and the House Armed Services Committee to look into the matter, and especially into the worry of some soldiers that their vehicles are unsafe.

"The unit felt that the vehicles they were required to drive weren't safe, both mechanically and in lacking armor to protect the personnel inside," he said. In addition, he said, the troops had expected to be protected by attack helicopters, but then were told that the aviation escort was unavailable.

The Army statement indirectly confirmed some of those assertions, saying that a safety stand-down is being conducted under which all the unit's trucks will be inspected. "Initial indication is that the solders scheduled for the convoy mission raised some valid concerns and the command is addressing them," the statement said.

The roadworthiness of trucks is a major concern of troops operating convoys in Iraq because the entire convoy has to pause whenever one breaks down, making the soldiers easy targets. Operating supply convoys is among the most hazardous of duties troops face in Iraq because attacks can occur anywhere along the way. The 343rd frequently hauls fuel, which heightens the danger of its supply missions.

Research editor Lucy Shackelford contributed to this report.