ERBIL, Iraq (Reuters) - Three Kurdish Peshmerga fighters were killed and five wounded on Saturday when an explosive device blew up near their vehicle south of the Iraqi oil city of Kirkuk, security sources said. The explosion happened in Daquq, a region bordering Islamic State-held areas, the sources said. It took place as the Kurdistan Regional Government prepares for a referendum on Monday on independence for the region under its control in northern Iraq, including Kirkuk, a multi-ethnic region also claimed by the central government in Baghdad. 