President Goodluck Jonathan declared a state of emergency in Borno, Yobe and Adamawa states, describing the insurgency in the northeast as a rebellion against the Nigerian state.
The declaration authorised a substantial deployment of troops and gave security agencies expanded powers of arrest and detention. Telephone networks were suspended in parts of Borno for extended periods during the operation.
Humanitarian agencies warned that the offensive risked displacing large numbers of civilians in a region already suffering from limited access to food, schooling and healthcare.
