WASHINGTON — Marine Lt. Gen. James Mattis told congressmen Thursday that a captain relieved of his command after complaining about the lack of armored Humvees was disciplined for unrelated reasons.

Capt. Kelly D. Royer, a unit commander with the 1st Marine Division’s Company E, was lauded by Marines officials in May 2004 for his leadership in a series of battles with insurgents in the Ramadi area.

But after he blamed many of the deaths in his unit on inadequate armor and equipment in a New York Times story several months later, Royer was relieved of command.

Mattis said the decision “had nothing to do with him speaking out” but instead was related to complaints from noncommissioned officers related to his command decisions.

The comments came after angry questions from Rep. Curt Weldon, R-Pa., who said he was “embarrassed” and “offended” by the way Marines officials had handled the situation.

“I don’t know him, but I do know he came out and publicly spoke out about his frustration,” Weldon said. “And instead of what should have been the proper response, which is to have everybody join in and fight the system and demand what he needed to protect those troops, it appears as though he is being singled out now.”

Mattis said he could not speak to specifics of the case because that would violate Royer’s privacy, but reiterated that the move was based solely on battlefield decisions. He also said the decision was made after careful research and deliberation.

“The last thing any battalion commander wants to do is to relieve a company commander of duty,” he said.

Nearly one-third of Royer’s 185-troop unit were killed or wounded during its six-month stay in Ramadi, which corps officials have said is the highest casualty rate of any deployed unit.