The Sahel is a largely semi-arid region on the southern fringe of the Sahara desert that cuts across several African countries.

While geographic delineations vary, the Sahel is typically defined as stretching from northern Senegal on the Atlantic Ocean coast, through parts of Mauritania, Mali, Burkina Faso, Niger, Nigeria, Chad, and into Sudan and Eritrea in the Red Sea.

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Many countries of the Sahel have been struggling with extreme climate shifts that result in recurring droughts with devastating effects on the already vulnerable populations residing in the underdeveloped region.

In recent years, parts of western Sahel have also been in the international spotlight due to a "fireball of conflict" that involves multiple armed groups, military campaigns by national armies and international partners as well as local militias.

The security crisis started in 2012 when an alliance of separatist and armed groups took over northern Mali, prompting a military intervention by former colonial power France to stop their advance towards the capital, Bamako, and prevent a total collapse of the Malian state.

But the fighting has sharply deteriorated in recent years as armed groups have expanded their reach, exploiting poverty as well as religious and ethnic divisions for recruitment.

Spiralling threat

While there is a multitude of non-state armed groups operating in the region, the two main actors behind increasingly sophisticated attacks in recent years have been the al-Qaeda-linked Jama'at Nasr al-Islam wal Muslimin (JNIM) and the ISIL-affiliated Islamic State in the Greater Sahara (ISGS).

Other groups operating in the wider region include al-Mourabitoun, Ansarul Islam, Plateforme, Ansar al-Din and Boko Haram.

According to the United Nations, attacks have increased fivefold in Burkina Faso, Mali and Niger since 2016, with more than 4,000 deaths reported last year in the border areas between the three hardest-hit countries.

The violence in the epicentre of the conflict has caused a major humanitarian crisis as attacks targeting civilians increase in number and frequency.

Over the past 12 months, more than 700,000 people were forced to flee their homes in Burkina Faso, according to the UN. Tens of thousands of Malians and Nigerien have also been displaced while thousands of schools have been shut.

Foreign forces deployed

A multinational military force comprising of troops contributed by the G5 Sahel regional body - Burkina Faso, Chad, Mali, Mauritania and Niger - has struggled to halt the violence since it began operations in 2017 amid persistent funding shortfalls and coordination disputes.

In early February, France, meanwhile, announced it was expanding its military presence in the region and sending an additional 600 troops to its existing 4,500-strong mission.

It came after a France-G5 Sahel summit in January ended with leaders agreeing to the creation of a new structure aimed at bringing the two parties' forces together under a single command, as well as facilitate joint operations and improve intelligence-sharing.

During the summit in Pau, French President Emmanuel Macron also sought a clear declaration by his counterparts confirming their preference for France's military engagement at the time of rising anti-French sentiment in some countries amid the swiftly deteriorating security situation.

Frustration over the perceived failure of French and UN forces to stem the tide of violence has been compounded by alleged human-rights abuses - including unlawful killings - during military operations of the national armies in the region.

Aid groups have also said that the military response in the region "is part of the problem", with observers warning that social and economic challenges would also need to be tackled in order to stem the crisis.

In September, leaders of the regional bloc the Economic Community of West African States (ECOWAS) announced a billion-dollar plan to help in the fight against armed groups.

The financial aid is expected to run between 2020 and 2024 amid concerns by a number of West African countries of also been hit by attacks.