American lawmakers have overwhelmingly backed a proposal to provide Israel with $205m (£142m) to speed up the deployment of a short-range anti-missile system.
The US House of Representatives voted 401-4 in favour of President Barack Obama's plan to fund Israel's Iron Dome project, designed to protect the country from rocket and artillery shell attacks.
"With nearly every square inch of Israel at risk from rocket and missile attacks, we must ensure that our most important ally in the region has the tools to defend itself," House Foreign Affairs Committee Chairman Howard Berman said.
The anti-missile system is designed to thwart attacks by Palestinian militants in the Gaza Strip and Hizbollah in Lebanon by blowing up rockets in mid-air.
Israeli defence officials have reportedly struggled to find the funds to make the system operational after successful tests earlier this year.
Analysts said the US donation is a sign that the Obama administration wants to rekindle relations with the Israeli government; these had been severely strained by Israel's announcement in March that it would build hundreds of new Jewish homes in Arab-dominated East Jerusalem, which was captured by Israel in 1967 and later annexed.
"The Obama administration has been trying hard to change the atmospherics," said Jonathan Spyer, senior researcher at the Centre for Global Research in International Affairs in Herzliya. "It didn't help their cause to be perceived as humiliating the Israeli government."
Israel ordered the Iron Dome project three years ago after its 2006 war with Lebanon, during which thousands of rockets landed in Israeli territory. Some 1,200 Lebanese, mostly civilians, were killed in the conflict, as were 160 Israelis.
Rockets fired by Palestinian militants from the Gaza Strip prompted Israel to launch a devastating military offensive on the tiny coastal enclave two winters ago that killed up to 1,400 Palestinians and 13 Israelis.
Although an effective deterrent system could make another debilitating regional conflict less likely, critics of the Iron Dome project say it is very costly and would not be able to shoot down missiles fired from a short distance away.
"The flight-time of a Qassam rocket to Sderot [an Israeli town close to the Gaza border] is 14 seconds, while the time the Iron Dome needs to identify a target and fire is something like 15 seconds," according to a military analyst quoted earlier this month in The Jerusalem Post.
However, the Iranian-backed Hizbollah is widely seen by Israel as a far graver threat. The guerrilla group has amassed thousands of rockets near Israel's northern border and has warned it is prepared to fire them if provoked.