A House panel is boosting money for Israel's Iron Dome missile defense system by $680 million amid an election-year fight over whether President Barack Obama is doing enough for the longtime Mideast ally.

The Republican-controlled Armed Services Committee, which begins crafting a fiscal 2013 defense budget next week, plans millions more for the system designed to intercept short-range rockets and mortars, according to a congressional aide. The money would be in addition to the $205 million that the Obama administration and Congress agreed to in a special request in the 2011 budget and would cover several years, through fiscal 2015.

The aide spoke on condition of anonymity in advance of the formal announcement on the budget.

An increase in money for the program was expected as the Pentagon said last month that it would work with Congress to steer more funds to a system that has proven effective in intercepting rockets and mortars fired by Palestinian militants from Gaza. The budget plan also comes as the Obama administration tries to dissuade Israel from launching a potential unilateral strike against Iran to stop its disputed nuclear development program.

"Supporting the security of the state of Israel is a top priority of President Obama and Secretary (Leon) Panetta," the Pentagon said last month. "The Department of Defense has been in conversations with the government of Israel about U.S. support for the acquisition of additional Iron Dome systems and intends to request an appropriate level of funding from Congress to support such acquisitions based on Israeli requirements and production capacity."

In addition, since 1988 and the early days of U.S.-Israeli cooperation on missile defense, presidents have proposed a specific amount for the program knowing full well that Israel will contact members of Congress and ask that they come up with more money. Congress routinely complies.

Last year, lawmakers took the overall request of $106 million for cooperative U.S.-Israeli missile defense programs and added millions more, providing $216 million.

This year, Republicans see a political opening in the uneasy relationship between Washington and Jerusalem over Israeli settlements in the West Bank and the state of Mideast peace talks, further complicated by the administration's pressure on Israel to hold off on a possible military strike against Iran.

The Iranian threat to Israel has stoked the bitter rhetoric both in Washington and on the presidential campaign trail, where likely nominee Mitt Romney has accused Obama of throwing Israel under a bus and emboldening the Palestinians. The fierce talk reflects that Jewish voters, who comprise only 2 percent of the electorate nationwide, are a critical part of Obama's base and could be the difference in close battleground states such as Florida, Pennsylvania, Ohio and Nevada.

Obama's budget for next year calls for $3.1 billion in military assistance for Israel, a slight increase over the current level and the most for any foreign country. In February, Rep. Howard "Buck" McKeon, R-Calif., the chairman of the House Armed Services Committee, and Rep. Ileana Ros-Lehtinen, R-Fla., who heads the Foreign Affairs Committee, complained in a letter to Obama that his "record low" budget request jeopardized Israel's security.