(Updates with House of Representatives passage, adds background)
WASHINGTON, Aug 1 (Reuters) - The U.S. Congress approved $225 million in emergency funding for Israel's "Iron Dome" missile defense system on Friday, sending the measure to President Barack Obama to be signed into law.
The House of Representatives approved the funding by a 395-8 vote late on Friday, several hours after the Senate passed it unanimously.
The money would be used to replenish Israel's arsenal of Iron Dome interceptor missiles, many of which have been used to shoot down short-range rockets fired from Gaza into populated areas of Israel in the current three-week-long conflict.
An earlier version of the funding plan had failed on Thursday when Senate Republicans blocked a broader spending bill that was largely intended to provide money to handle the current immigration crisis at the U.S.-Mexico border.
But lawmakers in both chambers subsequently reached agreements to pass the missile funding measure separately.
The White House did not immediately respond to a request for comment on whether Obama would sign the legislation. However, several administration officials have made comments this week praising the Iron Dome system.
Because it is being treated as emergency spending - similar to that used by Congress to pay for wars and natural disaster relief - the $225 million can simply be added to the U.S. deficit. It does not need to be offset by other savings under congressional budget rules.
Israel's Iron Dome missile interceptor system, which was partly funded by the United States, has shot down most of the rockets fired at its cities by militants in Gaza, providing much greater protection for Israelis than during past conflicts.
The Iron Dome system is constructed by top Israeli defense contractors Elisra Group, Israel Aerospace Industries and Rafael Advanced Defense Systems. It uses some components made by U.S. defense contractor Raytheon Co.. (Reporting by Patricia Zengerle and David Lawder; Additional reporting by Roberta Rampton; Editing by Jonathan Oatis and Matt Driskill)