Four militants were killed and several others injured in airstrikes conducted by the Libyan national army near Libya's border with Tunisia Sunday, according to security sources.According to a security spokesman, the airstrikes targeted the Abu-Kammash area, where four Libya Dawn militants were killed and several injured, Xinhua reported."The air raid was followed by violent clashes between the secular-leaning forces and the Libya Dawn militants in the region," the spokesman said, adding that the borders have been temporarily closed due to the clashes.The national army's warplanes last month had targeted several cities and towns in western Libya, like Zuwarah, Zawiya, Sorman and Gharyan, which are all under the control of Libya Dawn militants.Libya's national army, along with some pro-secular militias, has engaged in many battles since mid-November, trying to regain control of the lost cities and towns.