Israel, US rehearse state of the art air defence umbrella by Gavin Rabinowitz

A massive air defence drill under way in Israel will join Israeli and US systems to create the world's most advanced anti-missile umbrella to protect the Jewish state, officials said on Thursday.

The Juniper Cobra 10 exercises, the fifth in a series of joint air defence drills between the allies, began this week and comes amid heightened tension between Israel and arch-foe Iran.

Some 1,000 US soldiers will take part in the two-week exercise combining Israeli and US systems to "create the world's most advanced air defence system to protect our citizens and homes from attack," the commander of Israel's Air Defence Corps, Brigadier General Doron Gavish, told reporters. Israeli and US commanders refused to describe the scenarios they are simulating, but said they would practise merging different anti-missile systems that defend simultaneously against long-, medium- and short-range missiles.

Israeli media reported that the exercise would likely include a scenario of a combined attack from Iran together with shorter range barrages from Syria and the Lebanese militant group Hezbollah. Rear Admiral John Richardson, the commander of the US forces, said systems used would include the American THAAD (Terminal High Altitude Area Defence), the ship-based Aegis Ballistic Missile Defence System, and the Patriot anti-aircraft system, as well as the Israeli Arrow (Hetz) II.

Israel and the US have cooperated in missile defence since the US sent batteries of Patriot missiles to Israel during the first Gulf War, when Saddam Hussein fired dozens of Scud missiles at Israel.

Israel's air defences have since been further tested. Hezbollah fired hundreds of rockets into Israel during the 2006 conflict in Lebanon and Palestinian militants have lobbed thousands of improvised rockets from the Gaza Strip.

The exercises were purely defensive and, planned nearly two years in advance, were not in reaction to any current world events, the generals said. But they come amid heightened tensions between Israel and Iran. Israel, the sole if undeclared nuclear-armed state in the Middle East, has never ruled out a resort to military action to stop Iran's nuclear drive which the West suspects is aimed at making nuclear weapons but Tehran insists is only for peaceful ends.

Iran for its part has recently tested missiles that put Israel within range and President Mahmoud Ahmadinejad has repeatedly said that the Holocaust was a "myth" and that Israel was doomed to be "wiped off the map."