Iran has successfully tested an optimized version of the solid-fuel Sejjil-2 deterrent missile on Wednesday.According to Iran’s semi official TV channel Press TV it is part of its long-term plans to defend the country's borders.The channel added that deterrent system was build as part of an effort to design a more accurate and swift missile than previous Iranian-made models.Iran had tested the initial version of the two-stage Sejjil-2 missile in May this year.