An explosion rocked a Hezbollah site in southern Lebanon Tuesday, residents said, a blast a military source close to the movement said was an accident. A resident of Ain Qana village said it shook with the blast at a house serving as "a Hezbollah centre" on its outskirts, and that members of the group had cordoned off the area as ambulance sirens wailed across the village. A military source said preliminary information showed it was a "Hezbollah centre". rh/ah/par