Barack Obama is to ask the US Congress for an extra $200m in military aid to help Israel get a short-range rocket defence system in place.
The system is designed to shoot down mortars and rockets from Gaza or Southern Lebanon with guided missiles.
The system, called Iron Dome, has gone through testing and installation will start later this year.
According to US State Department figures, direct military aid to Israel was $2.55bn in 2009.
This is set to increase to $3.15bn in 2018.
Easing tensions
A White House spokesman reaffirmed what he called the administration's "unshakeable commitment" to Israel's security - adding that Mr Obama recognised the threat posed by missiles and rockets fired by Hamas and Hezbollah.
Iron Dome was conceived and developed in Israel following the Lebanon war of 2006, during which Hezbollah launched about 4,000 rockets into northern Israel.
Southern Israel has also come under fire, with thousands of rockets and mortars fired by Palestinian militants.
Israel completed tests on the system in January. Officials say the next phase in its development is its integration into the Israeli army.
A BBC correspondent in Washington, Steve Kingstone, says Washington may be acting now to ease the recent tensions in its relations with Israel.
In March a diplomatic row erupted when approval was granted for new homes for Jews in occupied east Jerusalem. The decision came during a visit to the city by the US Vice-President Joe Biden.
The announcement on US funding for Iron Dome coincides with the resumption of indirect talks between Israel and the Palestinian Authority.
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