India successfully used a medium-range nuclear-capable Prithvi II missile to intercept another missile for the first time in a test Monday, officials and media said. "The test was a success," the official said. But refused to confirm that the missiles had hit each other. "We are analyzing the data," he said. If the Prithvi can be transformed into a viable missile-killer, it would vastly boost India's defensive capabilities, particularly against its neighboring Pakistan. The two longtime rivals are both nuclear-armed.