Israel and the US have launched a major air defence drill as part of what Israeli public radio called preparation for a face-off with Iran.

During the two-week manoeuvres, dubbed Juniper Cobra, some 1,000 US personnel will mesh ground and ship-based missile interceptors like the Aegis, THAAD and Patriot with Israel's Arrow II ballistic shield, defence officials said.

Spokesmen on both sides insisted the biennial drill was unrelated to world events, but Israel Radio quoted an unnamed commander as saying it served 'to prepare for a nuclear Iran'.

The US and other world powers are trying to talk Tehran into giving up nuclear technologies with bomb-making potential, while the Israelis watch warily from the sidelines.

Israel, which is assumed to have the Middle East's only atomic arsenal, has hinted it could resort to force to prevent its arch-foe attaining the means to threaten its existence.

Some analysts believe that tactical limitations, and US misgivings about pre-emptive strikes, may compel Israel to accept a more defensive posture with the help of its top ally.

Iran denies seeking the bomb and has threatened to retaliate for any attack by firing its medium-range missiles at Israel.