So far, the United States has provided $205 million to support the Iron Dome effort; Obama administration plans to request unspecified level of funding from Congress to help expand the system.

This year, Obama's budget requests $3.1 billion in security assistance to Israel, part of a 10-year, $30 billion U.S. commitment to the Jewish state's security. None of that is scheduled to fund Iron Dome.

Top Republicans have criticized Obama for what they described as inadequate funding of U.S.-Israeli missile defense cooperation in his 2013 budget request released in February amid deficit-reduction requirements.