Children are feared to be among the victims of a suspected Boko Haram bomb attack at a military checkpoint in Nigeria.
Three explosions struck near the north-eastern town of Biu on Thursday in quick succession, a frequent tactic of the Islamist group, which has not yet claimed responsibility.
Witness Auwalu Ibrahim, a local pro-government vigilante, said there were children around the checkpoint when the blasts went off.
“Everyone has been told to go home due to apprehension about the blasts,” he added.
Biu has been repeatedly attacked by Boko Haram militants, including a suicide bombing on Thursday that killed at least seven people at a market.
Today’s attack came less than a day after five Cameroonian soldiers were killed at a base near the Nigerian border.
Colonel Joseph Nouma said hundreds of suspected Boko Haram militants escaped back to Nigeria after looting scores of homes in the area around Waza and setting them on fire as they fled.
The renewed cross-border violence came as politicians from 10 central African countries were ending a meeting in Yaounde, the capital of Cameroon, to plan a joint military strategy to tackle the growing regional threat posed by Boko Haram.
The rise of Boko Haram
The rise of Boko Haram
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The leader of the Islamist extremist group Boko Haram Abubakar Shekau delivers a message. Boko Haram has claimed responsibility for the mass killings in the north-east Nigerian town of Baga in a video where he warned the massacre “was just the tip of the iceberg”. As many as 2,000 civilians were killed and 3,700 homes and business were destroyed in the 3 January 2015 attack on the town near Nigeria's border with Cameroon
2/19 Boko Haram
People displaced as a result of Boko Haram attacks in the northeast region of Nigeria, are seen near their tents at a faith-based camp for internally displaced people (IDP) in Yola, Adamawa State. Boko Haram says it is building an Islamic state that will revive the glory days of northern Nigeria's medieval Muslim empires, but for those in its territory life is a litany of killings, kidnappings, hunger and economic collapse
3/19 Boko Haram
Nitsch Eberhard Robert, a German citizen abducted and held hostage by suspected Boko Haram militants, is seen as he arrives at the Yaounde Nsimalen International airport after his release in Yaounde, Cameroon on 21 January 2015
4/19 Boko Haram
Officials of the Nigerian National Emergency Management Agency (NEMA) visit victims of a bomb blast in Gombe at the Specialist Hospital in Gombe. According to local reports at least six people were killed and 11 wounded after a bomb blast in a marketplace in Nigeria's northeastern state of Gombe on 16 January 2015. Islamist militant group Boko Haram has been blamed for a string of recent attacks in the North East of Nigeria
5/19 Boko Haram
People gather at the site of a bomb explosion in a area know to be targeted by the militant group Boko Haram in Kano on 28 November 2014
6/19 Boko Haram
People gather to look at a burnt vehicle following a bomb explosion that rocked the busiest roundabout near the crowded Market in Maiduguri, Borno State on 1 July 2014. A truck exploded in a huge fireball killing at least 15 people in the northeast Nigerian city of Maiduguri, the city repeatedly hit by Boko Haram Islamists
7/19 Boko Haram
President Goodluck Jonathan visits Nigerian Army soldiers fighting Boko Haram
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Displaced people from Baga listen to Goodluck Jonathan after the Boko Haram killings
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Nigeria's President Goodluck Jonathan speaking to troops during a visit to Maiduguri, the capital of Borno State; most of the region has been overrun by Boko Haram
10/19 Boko Haram
Members of the Nigerian military patrolling in Maiduguri, North East Nigeria, close to the scene of attacks by Boko Haram
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Boko Haram’s leader, Abubakar Shekau, appears in a video in which he warns Cameroon it faces the same fate as Nigeria
12/19 Boko Haram
South Africans protest in solidarity against the abduction of hundreds of schoolgirls in Nigeria by the Muslim extremist group Boko Haram and what protesters said was the failure of the Nigerian government and international community to rescue them, during a march to the Nigerian Consulate in Johannesburg
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Boko Haram militants have seized the town in north-eastern Nigeria that nearly 300 schoolgirls were kidnapped from in April 2014
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A soldier stands guard in front of burnt buses after an attack in Abuja. Twin blasts at a bus station packed with morning commuters on the outskirts of Nigeria's capital killed dozens of people, in what appeared to be the latest attack by Boko Haram Islamists, April 2014
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The aftermath of the attack, when Boko Haram fighters in trucks painted in military colours killed 51 people in Konduga in February 2014
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The leader of Boko Haram, Abubakar Shekau (with papers) in a video grab taken in July 2014
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Ruins of burnt out houses in the north-eastern settlement of Baga, pictured after Boko Haram attacks in 2013
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A Boko Haram attack in Nigeria, 2013
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Abubakar Shekau, Boko Haram’s leader
Its assaults on the Nigerian military and civilians have killed thousands since the group launched its violent campaign to establish a hardline Islamic caliphate in 2009.
After five years fighting the Nigerian government in a bloody insurgency from strongholds in the north, Boko Haram has started to push into neighbouring Niger, Chad and Cameroon.
The group has become the main threat to the stability of Africa's biggest economy and leading oil producer, as well as to the surrounding region.
On Monday Boko Haram released a statement threatening to launch suicide bombings in Niger, Chad and any other countries joining the international military coalition fighting it.
In a translation published by the SITE Intelligence Group, a spokesperson said Niger was being dragged into a “swamp of darkness” after striking the town of Diffa.
“If you insist on continuing the aggression and the coalition with the government of Chad, then we give you glad tidings that the land of Niger is easier than the land of Nigeria and moving the war to the depth of your cities will be the first reaction toward any aggression that occurs after this statement,” the statement said.
Tens of thousands of people marched through Niger's capital of Niamey on Tuesday to support the military following a series of Boko Haram attacks along the border.
Nigerian soldiers recaptured two towns on Monday as the US and regional troops began manoeuvres in Chad as part of a growing international campaign.
Boko Haram was cited as a reason for postponing the election that was due to take place on Saturday by six weeks.
Its insurgency left an estimated 10,000 people dead last year alone. The violence has forced some 157,000 people to seek refuge in Niger, while 40,000 others have gone to Cameroon and 17,000 are in Chad, the UN said.
Additional reporting by agenciesReuse content