A powerful bomb killed six people and wounded twenty Tuesday in one of the deadliest attacks in recent months in Thailand's insurgency-plagued south, said army spokesman. An explosive, planted in a motorcycle gas tank, was detonated as two suspected Muslim insurgents rode a motorcycle pass a roadside restaurant, Army spokesman Col. Akara Thiprote said in a telephone interview. "We suspect that the bomb went off in front of the restaurant before they intended it to," Akara said, adding that the two were killed instantly. Two other victims were restaurant workers. The other two were people standing outside the open-air restaurant.