A magnetic bomb detonated on a diplomatic car in New Delhi. The police uncovered a cache of explosives at a golf course in the Kenyan city of Mombasa. Five Israeli tourists and a Bulgarian bus driver were killed in an attack outside the airport in the Black Sea coastal city of Burgas. These were just a few of what some Israeli and American intelligence officials say were nearly a dozen plots that form the backbone of a continuing offensive by Iran andHezbollah against Israel and its allies abroad. But the links seem tenuous at times, the tactics variable, the targets scattered across the globe, from the Caucasus to Southeast Asia to the Mediterranean.