WASHINGTON — Relations between the American military and Defense Secretary Rumsfeld plunged to a new low yesterday over claims by the head of the U.S. Army that the Pentagon’s budget proposals would leave his forces billions of dollars short of their needs.

In an unprecedented move that underlines the dire state of relations between the uniformed military and their civilian leaders, the Army’s chief of staff, General Peter Schoomaker, has refused to submit his 2008 budget to the Pentagon.

He made his protest after the White House and Congress ordered deep cuts to the Army’s requests.

It reflects a growing sense among generals that their forces are being stretched to their limits by their commitments in Iraq and Afghanistan without receiving adequate funding to fulfill them.

Traditionally, budgetary disputes are resolved in negotiations between the Pentagon and Congress. But General Schoomaker escalated the dispute into a confrontation with Mr. Rumsfeld by ignoring the budget deadline of August 15.

“This is unusual,” a senior Pentagon official involved in the budget discussions told the Los Angeles Times. “But hell, we’re in unusual times.”

General Schoomaker was looking for $138.8 billion in 2008, nearly $25 billion above the limits set by Mr. Rumsfeld, the newspaper said.

Most of the financing of the wars in Iraq and Afghanistan has come from emergency spending bills, leaving the annual defense budget to pay for personnel costs and weapons procurement.

But the Army argues that its share of the regular budget is insufficient to fund its role in the fight against terrorism, and in particular the high costs of replacing and repairing equipment used in Iraq.

General Schoomaker recently testified to Congress that he would need an extra $17 billion next year to pay for the repair of hundreds of tanks and armored vehicles. “There is no sense in us submitting a budget that we can’t execute,” he said.

Mr. Rumsfeld has set up a task force to investigate the funding dispute. But even if he backs down, the Army will almost certainly then face a fight with the White House and Congress.

A Pentagon spokesman played down the conflict, arguing that a delay in the budget was not surprising given that it came against the backdrop of the recent defense review, conducted every four years.

But Mr. Rumsfeld’s critics seized on the news of the stand-off to press home their argument that the armed forces are close to breaking point.

Colonel Larry Wilkerson, who was the chief of staff to the secretary of state in President Bush’s first term, Colin Powell, said his own estimates were that the army was between $35 billion and $60 billion short of its needs.

“You certainly run out of money fast,” he told the Daily Telegraph, adding that fewer helicopters were flying in Iraq and Afghanistan than a year ago because the “costs are unbelievable.” Morale in the military “is as low as they’ve ever seen it,” he added.

The strains on manpower were further evident when it emerged that the Army had extended the tours of about 4,000 soldiers for several more weeks in Iraq’s troubled Anbar province.

Mr. Rumsfeld did not provide a comment on the showdown with General Schoomaker.

Military analysts suggested that the fact that the stand-off had been leaked was the latest sign that soldiers and officials were trying to exonerate themselves over the situation in Iraq.

“If victory has a thousand fathers, defeat is a noisy orphan,” a military analyst at the New America Foundation think-tank, James Pinkerton, said. “The generals know Rumsfeld is the enemy, and they hope to get a better deal out of his successor.”