An experiment on the Arrow
An experiment on the ArrowIsrael news photo: IDF spokesman

Israel is racing against an attack by Iran and Syria and is upgrading its US-backed Arrow missile shield in the wake of a possible a chemical weapon attack from Syria, a defense official told Reuters Sunday.

The new "Block 4" generation of guided interceptor rockets, radars and technologies for synchronizing Arrow with U.S. systems was being installed in deployed Israeli batteries, a process that would take several weeks, the official told the news agency.

The Arrow system, operational since 2000, is designed to blow up incoming missiles at altitudes high enough for non-conventional warheads to disintegrate safely.

"It is part of the technological race in the region," added the official, who insisted on anonymity,

Besides the threat of a nuclear threat for Iran in the next year or two, Israel is now preparing for a possible chemical warfare attack from Syria, where the civil war could spur Syrian President Bashar Assad to turn his missiles on Israel. The same situation could arise if Hizbullah, which is thought to have accessed part of the chemical arsenal, decides to attack Israel from Lebanon.

Israel has threatened to attack preemptively in both countries, a prospect that could trigger a wider war and clash with Washington's efforts to resolve the crises diplomatically.

The Pentagon and U.S. firm Boeing Co. are partners in Arrow, an investment that the Obama administration hopes will help stay the Israelis' hand, according to Reuters.

U.S. Secretary of Defense Leon Panetta said last week that Arrow, like a similar Israeli interceptor for short-range guerrilla rockets, Iron Dome, was "designed to prevent wars".

Israel is developing Arrow III, which is due to be operational in 2014 or 2015, while deploying the current Arrow II. Unlike previous generations of the interceptor, Arrow III will engage incoming missiles in space, using detachable warheads that, turning into "kamikaze" satellites, will seek out and slam into the target.

Israel is also working on a more powerful rocket interceptor than Iron Dome, known as David's Sling or Magic Wand, which is due out next year. Meshed together and with U.S. counterparts, the three Israeli systems would form a multi-tier shield providing several opportunities to intercept incoming missiles.