Nigeria has begun the "final onslaught" against Boko Haram, the country's national security spokesman says, after the militants were ousted from the strategic town of Bama.
On a visit to London, Mike Omeri told AFP on Tuesday that "significant strategic military successes and gains" had been made against the Islamists in recent weeks.
"Bama (the second biggest town in Borno state) was retaken yesterday (Monday) and we have Abadam, Gwoza and Askira as part of the remaining areas where we still have this presence," he said.
Omeri said troops were "en route to the final onslaught because it has started already from Bama."
Abadam, Gwoza and Askira are also in Borno, which has been worst hit by six years of violence and was under emergency rule from May 2013 to November last year with neighbouring Yobe and Adamawa.
The military announced that Adawama was "cleared" last Friday and that Yobe was retaken on Monday from Boko Haram, who have pledged allegiance to the Islamic State group in Syria and Iraq.
There was no independent verification of the claimed successes, which followed the deployment last month of troops from Cameroon, Chad and Niger, as well as foreign mercenaries.
The operation not only aims at reducing the regional threat from the militants but also to secure the northeast for elections to be held on March 28.
Omeri refused to be drawn on when the insurgency would be declared over, although President Goodluck Jonathan said in an interview published last Wednesday that Borno would be free in three weeks.
