US lawmakers have voted to restrict the export of a type of cluster bomb that has been blamed for the indiscriminate killing of thousands of civilians across the globe. Cluster bombs open in flight and typically scatter hundreds of small bomblets across a wide area. Some fail to explode immediately and can cause death or debilitating injuries if disturbed, often years after a conflict ends. Frequently, victims are children. Israel dropped an estimated 4 million bomblets in southern Lebanon in its war against the Hizbullah guerrillas last year, and an estimated 1 million did not explode. There were reports that Hizbullah retaliated with cluster bombs of their own.