Prelude

After their massive losses in 2015, Barnawi's ISWAP and Shekau's Boko Haram both reconsolidated, though ISWAP grew into the more powerful group. Whereas Shekau had about 1,000 to 1,500 fighters under his command by late 2018,^[11][12] the Islamic State loyalists counted about 3,000 to 3,500 troops.^[11][13] Furthermore, ISWAP displayed signs of increasing sophistication and growing connections to ISIL's core group.^[12][13] Barnawi's followers did not just align ideologically with ISIL, but also adopted its technologies and tactics. They began using suicide vehicle-borne improvised explosive devices^[12] and drones which experts considered proofs of support and advice by exiled ISIL members from Syria and Iraq.^[12][13] In addition, ISWAP deviated from Shekau's brutal and autocratic leadership style by organzining a powerful shura or committee that gave the group an element of "democracy". As result, ISWAP gained more popular support, yet also became more prone to leadership struggles.^[14]

As ISWAP grew closer to its parent organization, it also became more hardline in its policies, resulting in a renewed internal struggles. Following the Dapchi schoolgirls kidnapping in February 2018, ISIL central command ordered the purge of Mamman Nur and his followers within ISWAP. Although Nur was a close ally of Barnawi and had risen to the de facto leader of ISWAP (with Barnawi serving as figurehead), the order was carried out, and Nur killed by his comrades. As he was believed to be a moderate, Nur's death was interpreted as sign that ISWAP was directed by the ISIL central leadership to fully restart its war against the local governments which resulted in the Chad Basin campaign from late 2018. Furthermore, ISWAP and Boko Haram agreed to a ceasefire, allowing both groups to focus yet again on their insurgency.^[12]

It has also been speculated that ISWAP decided to become more aggressive in order to prevent al-Qaeda affiliate Jama'at Nasr al-Islam wal Muslimin from gaining influence in Nigeria, especially as another Islamic State faction in West Africa (namely the "Islamic State in the Greater Sahara") had lost numerous of its fighters to defections to al-Qaeda.^[12]

Insurgent offensives

ISWAP began to launch a series of intense attacks on Nigerian Army positions near Lake Chad from early November 2018, scoring a number of victories (most notably near Metele) and killing over a hundred government troops between 18 and 22 November. Following the success of these raids, ISWAP overran and captured the village of Kangarwa near Lake Chad, where it also seized military equipment such as one tank. Though Kangarwa is a small settlement, and strategically not important, it demonstrated the militants' ability to still conquer and hold territory.^[15][16] Insurgents also launched several raids into Niger in course of November, kidnapping about a dozen girls from border villages.^[17] Shekau's Boko Haram launched at least one major attack in November, raiding a military base in Borno State.^[12] Rebel forces also targeted some villages in northern Cameroon, prompting local authorities to reactivate a number of village self-defense militias.^[18]

The Islamic State fighters continued their offensive in Borno State by attacking and reportedly capturing Arege on 30 November after a failed attempt two days earlier,^[19][20] and also launched further raids on Nigerian Army positions. Military bases which were attacked, though not captured by ISWAP, included Gambaru (1 December), Buni Gari (3 December),^[19][20] Mallam Fatori (3 December), and Gudumbali (4 and 14 December). In contrast, ISWAP managed to capture the villages of Cross Kauwa, Kukawa, Kekeno, and Bunduram sometime in December, and also overran a base at Mairari on 17 December, though retreated from it shortly afterward. Meanwhile, Shekau's Boko Haram also increased its attacks, though to a lesser extent than ISWAP,^[20] and began to greatly increase its propaganda output.^[21]

ISWAP attacked the harbor town of Baga at the shore of Lake Chad on the night of 26–27 December, and overran its garrison after heavy fighting. The local military base was plundered, the local Multinational Joint Task Force (MJTF) headquarters destroyed, and the naval base set aflame, while the militants managed to take control of tanks, APCs, boats, and much other equipment. Hundreds of local civilians fled the town after the takeover,^[22] even though the rebels had pledged to leave the local civilians alone.^[13] With the fall of Baga, rebels controlled most of Lake Chad's shoreline. The MJTF troops that survived the attack on Baga retreated to another harbor base at Fish Dam in Monguno. Militants launched three attacks on Monguno on 29–30 December, though these were repulsed.^[20]

At the same time, the MJTF member states began to prepare counter-offensives in order to push the insurgents back. The Nigerian Army was preparing a counter-attack to retake Baga by 31 December,^[20] though ISWAP still held the town by mid-February 2019.^[13] In contrast, an offensive by Niger reportedly met with more success. The Niger Armed Forces began to target islands on Lake Chad, and the area along the Yobe River at the Niger-Nigeria border from 28 December. While the Niger Army advanced on the ground, the Niger Air Force launched intense airstrikes, with the Nigerien government claiming to have killed 287 rebels by 2 January 2019.^[17] The Cameroonian Armed Forces also mobilized their troops in the north to counter the Islamist rebels.^[4]

On 13 January, ISWAP attacked a military base near Magumeri.^[8] On the following day, Shekau's Boko Haram attacked the refugee town of Rann which had been reportedly abandoned by its Nigerian garrison shortly before.^[23] The insurgents proceeded to destroy much of the settlement, including local clinics,^[24] causing much of the local civilian population to flee, with about 9,000 crossing the border and relocating to Bodo in Cameroon.^[8][24][25] ISWAP also raided Gajiram on 16 January.^[8] In the next days, the Nigerian Army and Cameroonian Armed Forces retook Rann.^[23] Authorities consequently forced most of the refugees who had fled to Cameroon to return to Nigeria.^[24] On 23 January, the Cameroonian military retreated from Rann, whereupon the Nigerian soldiers also withdrew, as they considered the town undefendable without Cameroonian help.^[23] About 35,000 residents of Rann promptly fled, believing that Boko Haram would surely return with the government troops gone. Most relocated to Goura in Cameroon, and this time the authorities allowed them to stay.^[24] As expected, Boko Haram indeed raided Rann after its garrison had left, setting the settlement ablaze, and murdering 60 people, including the local elders.^[24] More people subsequently fled,^[23] with about 60,000 being displaced in the region by early February.^[24] Overall, 39 insurgent attacks were recorded in Nigeria's Borno and Yobe States in January 2019,^[13] while five attacks took place in Cameroon from 1 to 22 January.^[4]

A series of clashes between the Nigerian military and ISWAP occurred near Mallam Fatori at the Nigerian-Nigerien border in early February, with both sides claiming to have inflicted heavy casualties on their opponents.^[26] From 14 to 16 February, insurgents launched a number of major attacks, targeting Maiduguri, Buni Yadi in Yobe State, and the border village of Chetima Wangou in Niger. Whereas the rebels managed to capture a military base near Maiduguri, the assaults on Buni Yadi and Chetima Wangou were reportedly repelled amid heavy insurgent casualties, including several military vehicles.^[27]

Operation Yancin Tafki