Updated

WASHINGTON -- The Pentagon on Thursday ordered a halt to work on an alternative engine for a next-generation warplane, angering congressional backers who vowed to fight President  Obama and Defense Secretary Robert Gates to save the program.

"The administration and the Department of Defense strongly oppose the extra engine program," the Pentagon said, noting that Obama did not include money for a second engine for the F-35 Joint Strike Fighter in his budget for the next fiscal year.

"In our view it is a waste of taxpayer money that can be used to fund higher departmental priorities, and should be ended now," the Pentagon said in a statement announcing that it had issued an order to stop work. The order will last up to 90 days, while the engine's fate is being decided.

Gates has urged Congress to kill the second engine for several years, calling it an "unnecessary and extravagant expense." In congressional testimony, Gates said the second engine requires another $3 billion to develop. Spending that money "in a time of economic distress" is a waste, he said.

Proponents of the alternative engine disagreed -- and they complained loudly on Thursday.

Rep. Howard "Buck" McKeon, R-Calif., the chairman of the House Armed Services Committee, criticized the Pentagon decision and said backers of the second engine would try to keep it alive. McKeon complained that choosing one contractor to make the planes' engines amounted to the largest earmark in the history of the Defense Department.

"In this era of fiscal responsibility, I am stunned that the administration and the Congress would accept the argument that it is good policy to save a dollar today only to spend a thousand dollars tomorrow," he said in a statement.

Sen. Sherrod Brown, D-Ohio, said the Pentagon "may be on the other side of the Potomac River, but it's not on an island. It has to follow the law like everybody else. And it cannot thumb its nose at Congress and decide whether it will or will not obligate spending that has been signed into law by the president."

The current stopgap spending bill includes money for the alternative engine.

The Pentagon plans to buy engines for the F-35 Joint Strike Fighter solely from Pratt & Whitney of Hartford, Conn. General Electric and Rolls Royce, which is working on the alternative in Ohio and Indiana, opposed the move along with their congressional backers.

The crux of their argument is that forcing Pratt & Whitney to compete against them will produce more efficient, less expensive engines for the nearly 2,500 F-35 fighters the Navy, Air Force and Marine Corps plan to buy and fly over the next 40 years. Eliminating the GE-Rolls Royce team gives Pratt & Whitney a "$100 billion monopoly" on the engines, according to the two companies.

But last month, House Republican freshmen led the charge in voting to cancel $450 million for the alternative engine, going against Speaker John Boehner, R-Ohio, and other House GOP leaders.

The House vote was 233-198, with many lawmakers arguing that it was a surefire way to fulfill campaign promises to cut spending.

On Thursday, Sen. Susan Collins, R-Maine, a member of the Senate Armed Services Committee, welcomed the Pentagon's decision. Collins said the government "must eliminate programs like this that are duplicative and unnecessary."

During the 1980s, the Air Force had GE and Pratt & Whitney compete to manufacture and maintain F-16 engines, a contest that backers of the second engine say led to lower prices. A competition for F-35 engines would do the same, they say. But the Defense Department has said the financial benefits of the so-called Great Engine War were negligible.