WASHINGTON (AP) — The Obama administration unveiled plans Wednesday to create an elite corps of master teachers, a $1 billion effort to boost U.S. students' achievement in science, technology, engineering and math.

The program to reward high-performing teachers with salary stipends is part of a long-term effort by President Barack Obama to encourage education in high-demand areas that hold the key to future economic growth — and to close the achievement gap between American students and their international peers.

Teachers selected for the Master Teacher Corps will be paid an additional $20,000 a year and must commit to participate multiple years. The goal is to create a multiplier effect in which expert educators share their knowledge and skills with other teachers, improving the quality of education for all students.

Speaking at a rally for his re-election campaign in San Antonio on Tuesday, Obama framed his emphasis on expanded education funding as a point of contrast with Republican challenger Mitt Romney, whom he accused of prioritizing tax cuts for the wealthy over reinvestment in the nation.

"I'm running to make sure that America has the best education system on earth, from pre-K all the way to post-graduate," Obama said. "And that means hiring new teachers, especially in math and science."

The administration will make $100 million available immediately out of an existing fund to incentivize top-performing teachers. Over the longer term, the White House said it plans to launch the program with $1 billion included in Obama's budget request for fiscal year 2013.

But the House and Senate both voted down Obama's budget earlier in the year, making it far from certain that Obama will be able to get congressional approval to spend $1 billion on master teachers.

An aide to Rep. John Kline, R-Minn., chairman of the House Education and the Workforce Committee, noted that the federal government already has more than 80 teacher quality programs and said it would be foolish to pump money into programs that may be duplicative or unproductive.

"Republicans share the president's goal of getting better teachers in the classroom," said Kline spokeswoman Alexandra Sollberger. "However, we also value transparency and efficient use of taxpayer resources."

Education Secretary Arne Duncan said he expected the two parties to come together to support achievement in areas of high demand.

"This initiative has nothing to do with politics," Duncan said. "It's absolutely in our country's best long-term economic interest to do a much better job in this area."

A report released in February by the President's Council of Advisers on Science and Technology found that the U.S. must increase by 34 percent the number of students receiving degrees in science, math and related fields to keep up with economic demand.

The program will start with 2,500 teachers divided up among 50 different sites, the White House said, but will grow to include 10,000 teachers over the next four years. Obama, in partnership with a coalition of groups including the Carnegie Corporation of New York, has set a goal of producing 100,000 additional math and science teachers over the next 10 years.