LIBBY GEORGE GUNMEN have freed all 279 girls who were kidnapped from a boarding school in northwest Nigeria on Friday, officials have said. It was the second such abduction in just over a week and the third since December in Nigeria's north, where a surge in armed militancy has led to a widespread breakdown of security. There is growing public anger over the violence, prompting President Muhammadu Buhari to replace his military high command in late January. Following are details of the unrest affecting different regions. ARMED GANGS, NORTHWEST/NORTH-CENTRAL NIGERIA Armed gangs that rob and kidnap for ransom, commonly described…