Suspected Islamic gunmen fatally shot eight tribal leaders involved in efforts to broker a cease-fire between security forces and insurgents in Pakistan's volatile northwest, authorities said Monday. The tribal leaders were killed in separate attacks late Sunday and early Monday in South Waziristan, a mountainous region close to Afghanistan where al-Qaida and Taliban terrorists are known to operate, a security official and the military said in a statement. The suspected insurgents killed three of the men in a market in Wana, the region's main town, while the other five were killed in attacks on their homes, a security official and an intelligence official said. The men were scheduled to meet each other Monday in Wana to discuss the negotiations, the officials said, speaking on condition of anonymity because they were not authorized to talk to media. However, the military said in a statement that the eight tribesmen died in a single attack on the peace committee's offices in Shakai.