July and November. Escalation in fighting The increasing intensity of the insurgency prompted the Nigerian government to launch an offensive, and with the help of Chad, Niger, and Cameroon, they recaptured many areas that were formerly under the control of Boko Haram. In late 2014, Boko Haram seized control of Bama, Borno, according to the town's residents. In December, it was reported that "people too elderly to flee Gwoza Local Government Area were being rounded up and taken to two schools where the militants opened fire on them." Over 50 elderly people in Bama were killed. A "gory" video was released of insurgents shooting over a hundred civilians in a school dormitory in the town of Bama. 2015 Baga massacre Between 3 and 7 January, Boko Haram attacked the town of Baga and killed up to 2,000 people, perhaps the largest massacre by Boko Haram. Maiduguri bombing On 10 January, 19 people were killed in a suicide bombing at a market in Maiduguri. The city is at the heart of the Boko Haram insurgency. On 12 January, Boko Haram carried out an unsuccessful attack on a Chadian Army base. Counter-offensive against Boko Haram On 23 January, a coalition of military forces from Nigeria, Chad, Cameroon, and Niger began a counter-insurgency campaign against Boko Haram. In the early hours of 25 January, Boko Haram launched a major assault on the city. On 26 January, CNN reported that the attack on Maiduguri by "hundreds of gunmen" had been repelled, but the nearby town of Monguno was captured by Boko Haram. The Nigerian Army said they repelled another attack on Maiduguri on 31 January. On 4 February, the Chad Army killed over 200 Boko Haram militants. On 4 and 5 February, Boko Haram carried out a massacre in Fotokol, Far North Region, Cameroon, killing 81 civilians, 13 Chadian soldiers and 6 Cameroonian soldiers. On 6 February, Boko Haram attacked Bosso and Diffa in Niger. On 15 February, a suicide bombing occurred in Damaturu. On 17 February, the Nigerian military retook Monguno in a coordinated air and ground assault. On 22 February, a suicide bombing occurred in Potiskum. On 24 February, suicide bombings occurred in Potiskum and Kano. On 2 March, the Nigerian Armed Forces defeated Boko Haram in the Battle of Konduga. On 7 March, Boko Haram's leader Abubakar Shekau pledged allegiance to the Islamic State of Iraq and the Levant (ISIL) via