Updated

The commander of the reserve quartermaster company whose members refused an order to deliver fuel in Iraq last week has been relieved of his command, Pentagon sources told FOX News.

Senior investigating officers who were dispatched to the 343rd Quartermaster Company's (search) encampment in Tallil, Iraq, following the incident relieved the captain of his command Wednesday.

The Pentagon sources wouldn't say why the move was made, only that the captain was found to have been derelict in his duty.

On Monday, the U.S. military had said no decision had been made on whether to discipline the Army reservists, despite statements from their relatives that the soldiers would be discharged.

"It is too early in the process to tell if any disciplinary actions will be initiated," Maj. Richard Spiegel, spokesman for the 13th Corps Support Command (search) in Balad, said in an e-mail to The Associated Press.

Families of some soldiers involved said Monday the commanders did not act on complaints that the convoy was hauling contaminated fuel or that their vehicles were in poor working order and were not sufficiently protected with armor.

Spiegel said no decision will be made on discipline until the investigation is completed and recommendations are made. "I could not speculate as to why soldiers would be telling people that they are going to be discharged," he said.

The Army announced last week it was investigating up to 19 members of a platoon from the 343rd Quartermaster Company, based in Rock Hill, S.C., after they refused to transport supplies from Tallil air base near Nasiriyah to Taji north of Baghdad.

On Monday, Ricky Shealey of Quinton, Ala., father of one of the soldiers involved, told The Associated Press that his son, Spc. Scott Shealey, said the trucks earmarked for the mission had hauled jet fuel and were then loaded with diesel fuel without purging the tanks.

"The fuel was mixed and he wasn't going on a mission to deliver fuel that could harm those with the helicopters," Ricky Shealey told the AP.

Shealey said his son spent three hours trying to convince his commander the mission "was inappropriate and it should not be done."

Shealey told CBS' "The Early Show" his son was told "he is going to be processed out of the Army with a general" discharge and was "very depressed about this."

A general discharge is consider a disciplinary action that would lead soldiers to risk losing most — if not all — of their veterans' benefits.

However, the commanding general of the 13th Corps Support Command, Brig. Gen. James Chambers, told reporters in Baghdad on Sunday that two investigations were under way and that 18 soldiers were involved. He also said none was under arrest and it was too early to tell whether the soldiers would be disciplined.

Shealey said his son refused to go on the mission because the fuel they were to haul was tainted and he feared it would be put in a helicopter that would later crash.

"The command just totally ignored them when they told them the fuel was contaminated and they was still going to send them out on this mission with contaminated fuel," Shealey told CBS. "The command was completely aware of the situation and I think it's a command issue and not a soldier issue."

Teresa Hill of Dothan, Ala., the mother of Spc. Amber McClenny, told NBC's "Today" show: "It was about the fuel. It was the broken-down trucks. Unarmored vehicles."

Chambers denied the fuel was contaminated.

He said the Army is adding steel armor plating on unarmored vehicles and upgrading maintenance. Some of the soldiers told family members they refused the assignment because they lacked proper equipment and protection.

The mission was later carried out by other soldiers from the 343rd, which has at least 120 soldiers, the military said.

Chambers has since ordered the 343rd to undergo a "safety-maintenance stand down," during which it will conduct no further missions as its vehicles are inspected, the military said.

The platoon has troops from Alabama, Kentucky, Mississippi, North Carolina and South Carolina.

The issue of lack of appropriate equipment has been a long-standing complaint by low-level soldiers and higher U.S. command.

Army Lt. Gen. Ricardo Sanchez (search), commander of U.S. forces in Iraq from mid-2003 until this summer, sent a letter to the Pentagon in December 2003 complaining that supplies were short and this was adversely affecting the ability of troops to fight, The Washington Post reported Monday.

Sanchez, who has returned to an assignment in Germany, told top Army officials in the Dec. 4 letter there was a severe lack of key parts for equipment vital to the mission, and the problem was so severe that "I cannot continue to support sustained combat operations with rates this low," the newspaper said.

Fox News' Ian McCaleb and The Associated Press contributed to this report.