WASHINGTON – The Obama administration Monday officially scrapped the alternate engine for a new generation of jet fighters, a move which means that GE Aviation in suburban Cincinnati will put off plans to hire hundreds of engineers for the project.

The decision, announced by the Pentagon, was not unexpected because Congress this year eliminated money in the 2011 budget to continue building the second engine. The engine — a joint effort by General Electric and Rolls Royce — was to have been built at the GE Aviation plant in Evendale.

But supporters of the project had hoped to add money to the 2012 budget to keep the second engine alive. GE officials expressed hope Monday that the engine could still be saved in the 2012 budget.

Rick Kennedy, a GE Aviation spokesman, said the company will not have to lay off any engineers or workers because the facility has landed two contracts to build engines for a business jet and a commercial jet. But he called the cancellation a “huge missed opportunity. We are losing an opportunity to hire hundreds of engineers here.’’

Both GE Aviation and Pratt & Whitney had been working on separate engines for the advanced F-35 Joint Strike Fighter. The Pentagon and other critics had insisted that it was not necessary to have GE Aviation build the alternate engine.

Sen. Rob Portman, R-Ohio, said “this decision is bad for taxpayers and our national defense.” Meghan Dubyak, a spokeswoman for Sen. Sherrod Brown, D-Ohio, said “Senator Brown is not done fighting to preserve the competitive engine which reduces costs for taxpayers in the long term.