Boko Haram kills scores in northeast Nigeria, militants amass in Gwoza

Boko Haram fighters killed 68 people, many of them children, in northeast Nigeria, as militants began amassing in the strategic town of Gwoza against a possible fight-back by military forces.
The atrocity in Njaba, some 50 kilometres (31 miles) from the Borno state capital, Maiduguri, happened at dawn on Tuesday and also saw attackers raze the village, witnesses and vigilantes said.
Nigeria, Cameroon, Chad and Niger last month began a joint operation against the Islamists, who have captured swathes of territory in the northeast and also begun cross-border attacks.
Since then, the military has claimed the recapture of several key towns, including Baga, on the shores of Lake Chad, where hundreds of people, if not more, are feared to have been killed.
On Thursday, Nigeria announced that troops were now in "full control" of Mafa, some 50 kilometres east of Maiduguri, "after completing the operation to clear terrorists from the town".
There was no independent verification of the claim.
But experts have said that with Boko Haram pushed out of its strongholds, deadly violence will continue, especially in remote areas and through suicide bombings in towns and cities.
- Slaughtered or shot -
Njaba village is 20 kilometres from the town of Damboa, which was seized by Boko Haram last June, forcing thousands to flee, but later recaptured by troops helped by local civilian vigilantes.
One woman, Falmata Bisika, 62, lost four of her grandchildren in the latest attack, which she said was carried out by gunmen "armed to the teeth" with weapons and explosives.
The militants destroyed homes and businesses with petrol bombs and shot anyone attempting to flee, "especially teenagers and the elderly", she said.
Muminu Haruna, 42, said he hid in a grain silo behind his house with about eight other people until the gunmen left at about 1:00 pm.
"I participated in the counting of dead bodies... 68 people were killed," he said in an account supported by two civilian vigilantes.
"These included both males and females, some were slaughtered and others shot dead and most of the houses in our village have been destroyed."
Haruna said the villagers had expected the attack, as other localities nearby have been targeted and because the village is en route from militant bases in the Gwoza forest and mountains.
- Militant build-up -
Some 100 kilometres from Damboa in Gwoza, which Boko Haram declared part of a caliphate last year and is considered its headquarters, militants began amassing and killed residents.
One woman who fled on Tuesday to the capital of neighbouring Adamawa state, Yola, said elderly men studying the Koran outside the home of a local cleric were shot dead in front of their wives.
Her account was backed up by local Senator Ali Nduwe, who speculated that the Islamists were preparing to defend the town from a military advance, possibly by Chadian troops in the area.
Reclaiming Gwoza would be a huge prize for Nigeria's military, as it battles to secure and stabilise the northeast in time for rescheduled presidential and parliamentary elections on March 28.
Observers have cast doubt on the six-week time-frame, given that Nigeria has been unable -- some say unwilling -- to end the violence in the six years since the start of the insurgency.
There are also lingering questions about whether some of the one million displaced by the conflict will be able to vote, even if the rebellion is finally put down.
Chad's well-trained army has offered a huge boost to Nigeria in recent weeks, recapturing towns in border areas and pushing into territory near Boko Haram's Sambisa Forest training camps.
Chadian President Idriss Deby on Wednesday claimed he knew where Boko Haram leader Abubakar Shekau was and called on him to surrender or be killed.
The Nigerian authorities have declared Shekau dead three times but the military has since reportedly said that they want the militant leader captured alive.