The African Union (AU) has announced the temporary deployment of a 3,000-strong force in West Africa's Sahel region where countries have struggled to combat multiple armed groups amid a swiftly deteriorating security situation.

Smail Chergui, head of the AU's Peace and Security Commission, said on Thursday the decision was taken during the bloc's annual summit in the Ethiopian capital, Addis Ababa, last month.

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"On the decision of the summit to work on deploying a force of 3,000 troops to help the Sahel countries degrade terrorist groups, I think this is a decision that we'll be working on together with the G5 Sahel and ECOWAS," Chergui told a news conference, referring to a 5,000-member joint force put together by regional countries and the bloc of West African states, respectively.

"I think this decision was taken because as we see, as you can recognise yourself, the threat is expanding, it's becoming more complex."

A localised revolt that began in northern Mali in 2012 has spread to the centre of the country and to neighbouring Burkina Faso and Niger.

About 4,000 people died in the three countries last year, a fivefold increase compared with 2016, according to the United Nations figures.

Last week, the UN said more than 4,000 people in Burkina Faso are being forced to flee as attacks on civilians by armed groups increase in number and frequency.

"By making the commitment public, Smail Chergui is clearly seeking to get the process moving, and encourage member states to commit forces," said Paul Melly, Consulting Fellow at Chatham House's Africa Programme.

"If they are to add value, the troops will need to be additional to those already provided by African countries to the UN peacekeeping force in Mali, or the joint force created by the five Sahelian countries themselves the G5 Sahel."

Many parts of the Sahel, a semi-arid swathe of land beneath the Sahara, that have seen the most fighting are severely underdeveloped. The several armed groups operating in the region, including the ISIL (ISIS) group and al-Qaeda, have exploited poverty as well as religious and ethnic divisions for recruitment. Meanwhile, the military campaigns by the ill-equipped national armies have also been marred by human rights abuses, which analysts say have pushed some civilians into the arms of fighters.

Forces in the region

The bloodshed has escalated despite the presence of a 13,000-strong UN peacekeeping force in Mali, and rattled coastal countries to the south of the Sahel.

Final decisions from the AU summit have yet to be published, but diplomats have confirmed details of the proposed Sahel deployment.

"The summit decided to deploy about 3,000 troops for a period of six months to work with the countries of the Sahel to deal with the menace that they are facing," Edward Xolisa Makaya, South Africa's ambassador to the AU, told AFP news agency.

"It's just a sign or a show of solidarity with the people of the Sahel."

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

Paris said the reinforcement would allow it to increase the pressure against ISIL in the Greater Sahel.

Melly, the Chatham House fellow, said the deployment of troops is a means to stabilising the region, which would later allow authorities to address the economic challenges that have exacerbated the crisis.

"Military deployment can never be the whole answer, but it has to be part of the solution, to relieve the immediate military threat posed by jihadist groups and gradually provide more secure conditions for the restoration of the public services and local development initiatives."

South Africa took over as AU chair at the summit and plans to host an extraordinary summit of the body on security issues in May.

Makaya said he hoped the Sahel deployment would take place "during the course of the year".

But many details of the possible deployment have yet to be worked out.

Makaya said no countries had come forward to volunteer troops, and it was also unclear how the deployment would be financed.