Israel has speeded up efforts to develop long-range cruise missiles of a type that could be used should the Jewish state try to strike at Iran's nuclear facilities, security sources said yesterday. Israel sent warplanes to destroy Iraq's main atomic reactor at Osiraq in 1981 and has not ruled out similar action to prevent its archfoe from getting the bomb should US-led diplomatic pressure on Tehran fail. The greater ranges to Iran's nuclear facilities might make cruise missiles more practical than planes, but the United States has rebuffed past Israeli requests to buy them. Cruise missiles are programmed to seek out and hit distant targets, flying low to avoid radar. But only the United States and Russia are known to have mastered all aspects of production.