Nigeria's military, on Saturday, claimed to have recaptured the town of Baga from Boko Haram, more than a month after it was overrun in what is feared to be the worst massacre of its six-year insurgency.
Defence spokesman Chris Olukolade claimed that "a large number of terrorists" drowned in Lake Chad as they tried to flee bombardment from air force jets.
The town, a fishing hub on the shore of Lake Chad in the far north of Borno state, northeast Nigeria, was recaptured on Saturday morning after the assault began the previous day, he added.
There was no independent corroboration of the claim, as thousands of Baga residents had fled the town after Boko Haram attacked on January 3 and hundreds, if not more, were killed in the following days.
Much of the town and 12 surrounding settlements were burnt to the ground.
Boko Haram's capture of Baga - and a military base used by a multi-national force in nearby Doron Baga - was seen as a strategic coup for the group, giving them control of Borno's entire border area.
It raised fears of attacks in neighbouring Niger, Chad and Cameroon, whose frontiers converge with Nigeria's on Lake Chad, but also a possible push south to the state capital, Maiduguri.
Niger attack
Nigeria's military this week announced the recapture of Monguno, a garrison town 65 kilometres from Baga, after ground and air strikes, and a push northeast was expected.
Troops from Nigeria have been joined by soldiers from Niger, Chad and Cameroon in recent weeks as a result of fears about the group's threat to regional security.
Olukolade said troops had to clear landmines before they were able to storm the town.
"Many of the terrorists died while an unknown but substantial number of them fled with various degrees of injury in the series of encounters along the routes of advance as troops headed for Baga," he added.
As in Monguno, the military said it seized and destroyed the insurgents' arsenal, including five anti-aircraft guns and rifles, as well as 34 motorcycles and five vehicles.
A cordon had been thrown around the town and 12 other locations nearby to allow soldiers to track down arms and ammunition as well as catch militants in the vicinity, he added.
Nigeria's apparent success in Baga came after Boko Haram attacked the village of Karouga near Lake Chad in southeastern Niger on Friday night, killing seven soldiers and losing 14 of its own fighters.
A Chadian security source said Boko Haram members later tried to cross into Chad across the lake but aircraft destroyed their five boats.
More than 13,000 people have been killed and over one million people left homeless since 2009, as the rebels try to carve out an Islamic state in northeastern Nigeria.
Since the attack on Baga, they launched their first raids on Niger and Chad to the north and also intensified assaults on the far northern region of Cameroon to the east.
French support
Presidential and parliamentary elections in Nigeria scheduled for February 14 were delayed by six weeks to March 28 because of the multi-national operation against Boko Haram.
Many, though, have viewed as unrealistic the deadline to secure and stabilize the northeast by polling day, to allow those displaced by the violence to return to vote.
Residents of Gamboru, on the border with Cameroon, on Friday returned to their homes for the first time since Chadian troops recaptured it.
"We met a ghost town strewn with burnt vehicles, destroyed buildings and emptied homes," Kachalla Moduye told AFP by telephone from Fotokol after a two-hour tour of the town.
In a sign of the growing international interest in the conflict, French Foreign Minister Laurent Fabius began a tour of west African countries involved in the fighting.
In Chad's capital, N'Djamena, he met President Idriss Deby and praised the country's contribution but said France did not envision any direct intervention in its former colonies.
Instead, France, which has a military base in N'Djamena, can provide tactical support and "coordination among the countries" as well as intelligence information.
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