SWAT (Agencies) - Four militants were killed and a security man sustained injures in a clash between the forces and insurgents in Mangaltan area here Sunday. Sources said on a tip-off, the security forces launched a search operation in Mangaltan, a mountainous area of the Swat Valley. During an exchange of fire, four miscreants were killed while a security man sustained wounds, the sourcess said, adding that the clash lasted for several hours. The injured was shifted to a hospital. The security forces had placed the area under curfew during the search, forcing the locals to remain indoors. No arrest was made during the operation.