One of the Chibok schoolgirls kidnapped by Boko Haram in 2014 has been rescued along with a 10-month old baby said to be her son, according to the Nigerian army.

Troops discovered the girl, named Maryam Ali Maiyanga, while screening escapees from Boko Haram's base on Saturday morning in Gwoza, a local government area of Borno State, according to Nigerian army spokesman Sani Usman.

Mr Usman said the girl was found carrying her baby son, named Ali - reportedly born to a Boko Haram commander - and that she was now undergoing medical tests.

According to Reuters, Mr Usman said: “She was discovered to be carrying a 10-month-old son, named Ali. She has been taken to the unit's medical facility for proper medical check up.”

The baby is thought to be fathered by a fighter from the Boko Haram, the islamist group that has killed 15,000 people and displaced more than two million over seven years, with the aim of creating an Islamic caliphate in north-east Nigeria.

In October, Boko Haram freed 21 Chibok schoolgirls after a deal was reportedly brokered between the group and the International Red Cross and Swiss government, which is said to have involved a "handsome ransom" of some millions of dollars being paid to the islamist group.

But President Muhammadu said he was not aware that any ransom had been paid and denied reports the government had swapped imprisoned Boko Haram fighters for the girls' release.

An estimated 270 schoolgirls were kidnapped from the northern Nigerian town of Chibok by the extremist group in April 2014. Dozens have since escaped but around 200 girls remain missing, causing global outrage.

The first returned Chibok girl, who was rescued in May when she was found pregnant in the forest where the girls had initially been taken, is reportedly still being held by the government to receive trauma counselling, at the reported dismay of her relatives.

The girl, named Amina Ali Nkeki, has said she still misses the man she was forced to marry during her captivity, who is suspected of being an Islamist militant, but who she says was also a victim of kidnapping and helped her escape.

The extremist group published a video in August apparently showing recent footage of dozens of the kidnapped girls, and said some had been killed in air strikes.

Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram Show all 16 1 /16 Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram Fifteen year old Nigerian refugee Fati, hugs her mother Mariam while carrying her sister, at the Minawao refugee camp in Northern Cameroon UNICEF Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram Fifteen year old Nigerian refugee Fati, carry her eight month old sister, who she last seen when she was 3 months old, at the Minawao refugee camp in Northern Cameroon. She was abducted by Boko Haram and spend four months in captivity. She was given to a man and forced to be his wife. She was eventually freed by Cameroonian soldiers and have been reunited with her family in a refugee camp in Cameroon UNICEF Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram Nigerian refugee's at the Minawao refugee camp in Northern Cameroon. The conflict in North-East Nigeria prompted by Boko Haram has led to widespread displacement, violations of international humanitarian and human rights law, protection risks and a severe humanitarian crisis. This is one of the fastest growing displacement crisis in Africa – one of the world’s most forgotten emergencies, with little attention from the donor community UNICEF Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram Nigerian refugee children at the Minawao refugee camp in Northern Cameroon UNICEF Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram Nigerian refugees line up to receive food aid at the Minawao refugee camp in Northern Cameroon UNICEF Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram Didja Damna (26) with her daughter, 17 month old Ngarvounsia, as she gets treatment at the Maroua hospital in Northern Cameroon UNICEF Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram Didja Damna (26) with her daughter , 17 month old Ngarvounsia, as she gets treatment at the Maroua hospital in Northern Cameroon. Didja have four other children and had her first child when she was sixteen. Ngarvounsia lost weight and have been treated for three day's in hospital and is recovering UNICEF Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram Fadi ,the wife of internally displaced Alagi Dubji feed her daughter, Ina Petal( 13 months) a peanut butter supplement, at their home in Maroua in Northern Cameroon. Ina received treatment for malnourishment and is doing well after she was discharged from the hospital. Alagi and his family had to flee from his village near Maroua after Boko Haram fighters burned down his house.Alagi had 40 children with 26 still alive UNICEF Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram A malnourished girl gets treatment at the Maroua hospital in Northern Cameroon UNICEF Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram More than 135 displacement sites have been noted along the border with Nigeria UNICEF Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram Temporary schools in the refugee camp of Kabelewa, counts eight classrooms for 549 pupils. Out of those 549 children, only 12 had already been to school before UNICEF Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram As the river continues to dry up in April and May, we expect to see an increase in violence in the Diffa region. Both refugees and internally displaced people are affected by the insecurity, fleeing attacks and also fleeing to safer locations ahead of attacks. Generally noticed is a movement from locations near the border towards the inland area along the main road where spontaneous new sites are being created and host villages' population increasing UNICEF Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram Forced displacement in the region of Diffa is becoming regular and is linked to the volatile security situation in the region. Diffa, the Niger's poorest region, has been affected by the consequences of the increased acts of violence in Nigeria, conducted by the armed group Boko Haram, increasingly expanding and targeting the civilian population in Niger - and Diffa region in particular. With water levels starting to fall, the Nigeria-based armed group is seizing the opportunity to cross over the Komadougou River, into Niger from Nigeria UNICEF Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram Fatima Abubakar, 13, in Dar Es Salam refugee camp, Lake region of Chad. Fatima lost five family members during the attack of her small village in Nigeria, in the shores of the lake Chad. She now lives in Dar Es Salam refugee camp, in Chad, with her father, mother and 3 siblings, "The table was all set and we were just about to have our breakfast together when the gunshots started outside. We immediately left in panic. I escaped with my mother. We left in two pirogues. My mother’s pirogue had a whole and they put a cloth to stop the water from entering. But they had to come back to shore. I thought I would be forever alone and that my parents were dead. I cried for days. When I met them both days later in Ngouboua (an island in Chad) I couldn’t be happier. I sometimes think about our table, where the breakfast was served, and how the house would be now" UNICEF Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram Hafsa Mohammed sews in the UNICEF-supported child friendly space in Dar Es Salam refugee camp, Lake region of Chad. Every child’s future starts with a dream and Hafsa Mohammed, 16, has a very clear idea of what she wants to become. She wants to be a successful businesswoman and own a notions store. She now lives in Daresalam refugee camp, Lake region of Chad. “I have started again to sew. I used to do it back in Nigeria. My parents encouraged me to do it. It will be useful for me to start my own business and I would be happy to teach others as well,” explains Hafsa UNICEF Beyond Chibok: Report shows alarming trends in countries affected by Boko Haram Salta Bintou Hassan is 11. She lost her arm after an suicide attack on Bagasola market in October 2015. After spending two months in the hospital of N'Djamena, she is back with her family. Yet, her life will never be the same UNICEF

President Buhari has vowed to secure the release of the nearly 200 schoolgirls who remain captive, but it has been reported that many of the girls are said to not want to leave their jihadist captors, either because they have been radicalised or because they are ashamed of their experience.

Nigeria's military has been carrying out a large-scale offensive in the vast woodland area and other parts of Borno state in the last few weeks, according to Reuters.