Nigeria's military on Saturday imposed a round-the-clock curfew in parts of the northeastern city of Maiduguri, the home base of Boko Haram Islamists, as a massive offensive against the insurgents presses on across the region.

"In order to sustain special operations in the face of recent Boko Haram attacks, (a) 24-hour curfew is hereby imposed in the following wards" of Maiduguri, a military statement said, listing 12 neighbourhoods considered Boko Haram strongholds.