Israel has successfully tested its upgraded Arrow missile interceptor, designed to defend against ballistic threats, for the second time.
The Arrow III is designed to deploy kamikaze satellites known as "kill vehicles" that track and slam into ballistic missiles above the earth's atmosphere, high enough to safely disintegrate any chemical, biological or nuclear warheads.
Iran and Syria have long had such missiles, and Israel believes some are now also possessed by their ally Hezbollah, whose growing arsenal in Lebanon, stocked in part by Damascus, preoccupies the Israelis as their most pressing menace.
The US-backed system is one of several elements of an integrated Israeli aerial shield, and today’s launch over the Mediterranean was the second flight of the system following one in February 2013, though it did not involve the interception of any target, officials said.
Israel deployed the previous version, Arrow II, more than a decade ago, rating its success in live trials at 90 per cent.
"The Arrow III interceptor successfully launched and flew an exo-atmospheric trajectory through space," Israel's Defence Ministry said in a statement.
Yair Ramati, head of the ministry's Israel Missile Defence Organisation, told reporters that as part of the test, which was attended by US officials, the interceptor jettisoned its booster and "the kill vehicle continued to fly in space (and) conducted various manoeuvres ... for a couple of minutes".
Israel predicts Arrow III could be deployed by next year. The Pentagon and Boeing are partners in the project run by state-owned Israel Aerospace Industries (IAI).
Arrow is the long-range segment in Israel's three-tier missile shield, which also includes the successfully deployed "Iron Dome", which targets short-range rockets and mortar bombs favoured by Palestinian guerrillas in Gaza, and the mid-range "David's Sling", which is still under development.
The United States and Israel have been jointly working on Arrow since 1988. Washington says helping Israel build up the capability to shoot down missiles staves off escalatory wars – or pre-emptive Israeli strikes – in the Middle East.
Israel also sees it as a means of weathering enemy missile salvoes while it brings its offensive capabilities to bear.
"Developing such systems will let Israel maintain routine life despite the threats facing us, and will assist the IDF (Israeli military) in prevailing in combat quickly and efficiently, if required," Defence Minister Moshe Yaalon said on Twitter.
The civil war in Syria has raised questions about President Bashar al-Assad's control over his own ballistic Scud missiles. Israel says Damascus has used around half of these against Syrian rebels.
Hezbollah is helping Assad battle the insurgency. Fearing the guerrillas might get advanced Syrian weaponry, Israel carried out at least three military strikes on suspected Lebanon-bound convoys last year, security sources said.
Such efforts may have had limited efficacy, however and a senior Israeli official told Reuters that they estimated Hezbollah now has between 60,000 and 70,000 rockets and missiles deployed throughout Lebanon, including a few dozen Syrian-supplied Scud Ds with ranges of 440 miles.
Hezbollah may also have hundreds of Fateh-110 missiles with ranges of 160 to 190 miles, the official said. Among the targets of the Israeli strikes on Syria last year, security sources said, was a shipment of Fateh-110s meant for Hezbollah.
"It's the most significant threat facing Israel today," the official said of the Hezbollah missiles.
"We believe more than half the rockets and missiles are operational. They are on launchers, ready for launch. It's just a matter of a decision."