Security around the borders between Niger, Mali and Burkina Faso has been torrid for years. AFP
With at least 90 people dead in two separate attacks close to the Niger and Mali borders, we look at Africa's increasingly troubled Sahel region.
The semi-arid zone has become a crucible of jihadist terror, climate change and population movement.
Here is a brief explainer on the region:
What Is It?
The Sahel, or Sahil in Arabic, meaning coast or shore, is a vast region that stretches along the southern rim of the Sahara desert from the Atlantic to the Red Sea.
Wedged between the desert to the north and tropical forests and savannah to the south, the belt has a tropical semi-arid climate.
Where Is It?
There is debate over of which countries actually belong to the Sahel.
But a core group -- Burkina Faso, Chad, Mali, Mauritania and Niger -- are gathered in an anti-jihadist alliance called the G5 Sahel.
Other definitions of the region take in parts of Senegal, Nigeria, Sudan, South Sudan and Eritrea.
Jihadist Hunting Ground
With vast stretches of inhospitable desert and porous borders, the central Sahel has become a hunting ground for armed groups, rebels, jihadists and criminal gangs.
Jihadist violence erupted after a rebellion in northern Mali in 2012. The conflict spread to the centre of the country and then to neighbouring Burkina Faso and Niger, claiming thousands of lives and displacing hundreds of thousands of people.
Several anti-jihadist military operations have been launched in the area, including the French operation Barkhane and the G5 Sahel force, which includes units from the five countries' armies.
Violence has spiked in the Tillaberi region of Niger bordering on Mali, Burkina Faso and Benin in recent months, with 100 people killed in early January in attacks on two villages there.
The area has also seen several high profile kidnappings, with at least six western hostages still held there.
As the world battles climate change, the effect of global warming is around 50 percent greater in the Sahel. In the last quarter of the 20th century, the region suffered the worst droughts anywhere on the planet.
This has contributed to a staggering 90 per cent decline of the surface of Lake Chad over the past six decades and a race is on to stop the main source of fresh water to 40 million people across four countries drying up.
In February 17 countries set down a plan to invest $400 billion in fighting climate change in the Sahel by 2030.
The region, which is broadly very poor, has one of the highest demographic growth rates in the world.
The population of the G5 Sahel region is expected to more than double to around 170 million by 2050, according to the United Nations.
Amid the unrest, poverty and climate change, the UN said internal displacement had increased 20-fold in less than two years and the number of families facing hunger has tripled.
The United Nations warned in November of a heightened risk of famine in Burkina Faso, along with northeastern Nigeria and South Sudan and also a high hunger risk in both Mali and Niger.
Problems have been exacerbated by the Covid-19 pandemic.