FOUR soldiers and a senior government official were killed in Cameroon's restive North West Region after their vehicle hit an improvised explosive device, according to an internal security note and another senior official. The vehicle was travelling in a military convoy when it was ambushed by armed secessionists, the note seen by Reuters said, adding that five others were severely wounded. The senior official said the five-vehicle convoy was returning to the town of Mbengwi, 450 km (279.62 miles) northwest of the capital Yaounde, after the installation of recently appointed local officials when the blast occurred. No one has claimed…