In an honest and upfront piece over on serious news outlet Something Awful, the President of Nigeria, Goodluck Jonathan, has explained the reasons behind his country's highly unpopular (with XCOM leaders) withdrawal from the XCOM project.
While a "tragic incident at the gas station" seems to have been the straw that broke this camel's back, he lists numerous grievances with XCOM command, including a decision to send their only Skyranger to France (ignoring Nigerian pleas) on a "UFO vacation" and a lack of satellite coverage.
Jonathan announced that, in place of XCOM personnel, his people's defence against the alien invasion would be handled by a new Nigerian body, called UFO Force. Apparently the organisation "is being given a new base in the former gas station missing several walls and partly on fire. I assure you the fire has not spread to the important parts."
Why Damned XCOM is Abolished From Nigeria [Something Awful]