Nigerian President Goodluck Jonathan has said he hopes that all territory seized by Islamist militant group Boko Haram will be retaken within a month.

"They are getting weaker and weaker by the day," he told the BBC.

But he admitted the security forces had been slow to respond to the insurgents' initial advance in north-east Nigeria.

Nigeria's army has recently claimed a series of victories over the militants. The violence has killed more than 15,500 people since 2012.

The president also said he believed the 219 schoolgirls abducted from Chibok by Boko Haram last year were still alive, adding that the authorities continued their search for them.

"I believe we'll get them," he added.

The interview came just days before Nigerians are due to vote in presidential elections.

Despite stiff competition from the opposition, Jonathan said: "I'll surely win."

(BBC)