Pentagon press secretary George Little said in a statement that short-range rocket defense system has been critical in recent weeks, when nearly 300 rockets were fired at southern Israel from Gaza.
The Iron Dome system intercepted more than 80% of its targets.
Little said the Pentagon and Israel have discussed US support for buying additional Iron Dome systems and will ask Congress for money.
The Iron Dome system received $205 million in 2011. The current budget has no money for the program.
Defense Minister Ehud Barak welcomed the statement, which he said reflects US Secretary of Defense Leon Panetta's willingness to assist Israel is purchasing additional barratries.
"I welcome the American administration's decision to aid in bolstering Israel's security," he said.
AP contributed to this report
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