The missile that the Israeli Arrow defense system was supposed to intercept in a failed drill on Thursday was an advanced version of the Iranian Shihab ballistic missile, which does not yet exist but will have superior radar-evading capabilities. Technical problems early Thursday led to the fourth cancellation of a test of the newly-upgraded Arrow missile defense system at a United States military missile range off the California coast. The test, officials said, was cancelled after the "enemy missile" - launched from a C-17 transport aircraft from 80,000 feet - was in the air. The cancellation was due to communication problems between the control room located on the coast and the missile launcher, deployed hundreds of kilometers away on an island opposite Los Angeles. The test was initially scheduled for last Tuesday but was cancelled due to bad weather and hurricane warnings. Subsequent tests planned for Monday as well as last Friday were also cancelled due to technical problems. Israeli defense officials said that had the test been conducted in Israel, the Air Force likely would have gone ahead with it despite the technical difficulties. The test, the officials said, would likely be held again in the near future. "The Americans want everything to work 100 percent," one official said. "It could be that the distance between the control room and the launcher was the problem." While the Arrow was not launched at the "enemy" missile, its systems tracked the target, which mimicked an Iranian ballistic missile, and exchanged data on the target in real-time with elements of the US missile defense system. "Not all test conditions to launch the Arrow Interceptor were met and it was not launched," the Pentagon said in a statement. Other objectives were achieved and the results were being analyzed, it said. Iran is working hard to increase the accuracy of its missiles. In November it successfully test-fired the Sajil, a solid-fuel, high-speed missile with a range of 2,000 km. Solid fuel is a significant breakthrough because it increases accuracy and can be launched immediately without the need to fuel the rocket first. Iran also has a number of BM25 intercontinental missiles that it purchased at least four years ago from North Korea. The missile that the Arrow was supposed to intercept was developed in the United States and has advanced radar-evading capabilities that include dispersing magnesium balls next to the engine and in mid-flight that heat up and create multiple targets on Arrow operator's radar screens. "Our assessment is that the Iranians will try to develop this capability," explained a defense official. "Our challenge is to see that the Arrow is capable of distinguishing between the missile warhead and the decoys."