Washington (CNN) -- With Congress battling over this fiscal year's budget, the Defense Department on Thursday issued a stop-work order on the controversial Joint Strike Fighter second engine.
"In our view it is a waste of taxpayer money that can be used to fund higher departmental priorities, and should be ended now," a Defense Department statement said of the planned alternative engine for the next-generation aircraft development program, which has been riddled with cost overruns and labeled unnecessary by critics.
Cost estimates for the second engine range from $1.8 billion to $2.9 billion.
President Barack Obama excluded funding for the second engine in his budget proposal, and the Defense Authorization Act for the current fiscal year also cuts the project.
However, the lack of a formal budget for this fiscal year -- 2011 -- means the government is funded under a continuing resolution based on previous spending levels, which includes money for the alternative engine.
Those in favor of the second engine say competition will drive down costs and lead to innovation.
"The department's decision is especially troubling when you consider their preferred engine has experienced development delays and a cost to complete increase of 445% over the last three years," said a statement by Rep. Howard "Buck" McKeon, R-California, chairman of the House Armed Services Committee.
"Going forward, we will explore all legislative options available to us to maintain engine competition in the largest acquisition program in U.S. history," McKeon said.
The House of Representatives voted to cut funding for the second engine in its budget proposal for the rest of this fiscal year, which ends September 30. That proposal was defeated in the Senate, which has yet to reach agreement on its own spending plan.