A Tunisian soldier was killed and five others injured on Friday in a landmine explosion during a sweeping operation against Islamist militants near the borders with Algeria, the defense ministry said. The explosion took place in the remote Mount Chaambi area, southwest of the capital Tunis, when a military vehicle was passing by, the ministry said, adding that a senior non- commissioned officer was killed and five other soldiers injured, two seriously. Security forces have been fighting Al-Qaeda-linked militants hiding near Tunisian-Algerian borders since 2012, but have so far failed to eliminate them and fully control that area. Mount Chaambi, which lies on those borders in the governorate of Kasserine, was declared a closed military zone after a group of militants were discovered to use the location as a refuge. More than 20 security personnel have been killed in the area since the beginning of the battle, mostly by improvised bombs and mines.