New reports have emerged on in-fighting between rival factions of the Boko Haram militant group, as the jihadists feel the pressure of a concerted Nigerian military push and the number of desertions continues to rise.

The apparent split in the group began last month when an Isis media wing announced Abu Musab al-Barnawi as the new leader of Boko Haram, which pledged allegiance to the Middle East insurgency in March last year.

But the previous leader, Abubakar Shekau, insists he is still in charge, and the AFP news agency quoted local sources saying deadly skirmishes have now broken out between supporters of either man.

Nigeria’s military has declined to comment on the development, but at least half a dozen Shekau supporters are reported to have been killed and more wounded in clashes across three villages in the Monguno area of Borno state.

Mele Kaka, who lives in the area, told AFP the Barnawi faction had launched the attacks in each case, on areas controlled by Shekau supporters.

After each attack, he said, the Barnawi fighters told villagers the other faction had “derailed from the true jihad” by killing innocent people and looting their property.

The Isis-supporting faction has previously rejected Shekau’s preferred strategy of suicide bombings in crowded areas. In comments shortly after he was named the new leader, Barnawi criticised his predecessor for “targeting the ordinary people”.

The Bloomberg news agency also carried reports of the skirmishes, which appear to have occurred late last week. News can take time to travel in Nigeria’s war-ravaged northeastern region, where up to 2.5 million people have been displaced from their homes and most basic infrastructure like telecommunications lines have been destroyed.

Ali Mohammed, a member of an army-supporting vigilante group based in Monguno, told Bloomberg around 18 Boko Haram fighters were understood to have surrendered to the army, along with their families, following the in-fighting.

“They are under custody of Monguno command and we believe the dual battle between Barnawi's and Shekau’s camps may have compelled them to sneak out and surrender,” he said.

Despite all its recent setbacks, Boko Haram continues to pose a serious threat to the region.

Yesterday a Reuters reporter who rode along with the Nigerian army reported soldiers firing indiscriminately into the bush throughout the journey, because of a constant fear of ambush.

The army has reclaimed a number of key towns in Borno state since former military leader Muhammadu Buhari became president last year and the military moved its base of operations to the northeast city of Maiduguri.

The rise of Boko Haram Show all 20 1 /20 The rise of Boko Haram The rise of Boko Haram Boko Haram 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 AFP The rise of Boko Haram 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 The rise of Boko Haram 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 The rise of Boko Haram 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 The rise of Boko Haram 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 The rise of Boko Haram 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 The rise of Boko Haram Boko Haram President Goodluck Jonathan visits Nigerian Army soldiers fighting Boko Haram Getty Images The rise of Boko Haram Boko Haram Displaced people from Baga listen to Goodluck Jonathan after the Boko Haram killings AFP/Getty The rise of Boko Haram Boko Haram 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 AFP/Getty The rise of Boko Haram Boko Haram Members of the Nigerian military patrolling in Maiduguri, North East Nigeria, close to the scene of attacks by Boko Haram EPA The rise of Boko Haram Boko Haram Boko Haram’s leader, Abubakar Shekau, appears in a video in which he warns Cameroon it faces the same fate as Nigeria AFP The rise of Boko Haram Boko Haram Nana Shettima, the wife of Borno Governor, Kashim Shettima (C) weeps as she speaks with school girls from the government secondary school Chibok that were kidnapped by the Islamic extremist group Boko Haram, and later escaped in Chibok The rise of Boko Haram 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 The rise of Boko Haram Boko Haram Boko Haram militants have seized the town in north-eastern Nigeria that nearly 300 schoolgirls were kidnapped from in April 2014 AFP The rise of Boko Haram Boko Haram 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 The rise of Boko Haram Boko Haram The aftermath of the attack, when Boko Haram fighters in trucks painted in military colours killed 51 people in Konduga in February 2014 AFP/Getty Images The rise of Boko Haram Boko Haram The leader of Boko Haram, Abubakar Shekau (with papers) in a video grab taken in July 2014 AFP/Getty The rise of Boko Haram Boko Haram Ruins of burnt out houses in the north-eastern settlement of Baga, pictured after Boko Haram attacks in 2013 AP The rise of Boko Haram Boko Haram A Boko Haram attack in Nigeria, 2013 AFP/Getty Images The rise of Boko Haram Boko Haram Abubakar Shekau, Boko Haram’s leader AP

But heavy rains have halted its advance towards the Sambisa forest, which the government describes as Boko Haram’s final bolthole, whose dirt roads are ill-suited to heavy tanks and artillery.

Food is scarce in the areas still controlled by Boko Haram and the group is reported to be low on other supplies and ammunition. But the shortages are hurting those still living in the area just as much as it is the militants.

"We had to leave the bush because we were hungry," said Haja Jamil, 40, a pregnant yet painfully thin woman who arrived at the recently liberated city of Bama two weeks ago with two children.