UN Secretary-General Antonio Guterres warned Monday that Africa's Sahel region was descending into all-out violence and said the United Nations must help the region confront the threat from Islamist militants.

In a report to the Security Council obtained by AFP, Guterres said the United Nations and other donors should shore up a regional force set up by Burkina Faso, Chad, Mali, Mauritania and Niger.

The situation in the Sahel is "extremely concerning," Guterres said in the report released just days before Security Council ambassadors travel to the region for talks on the security crisis.

"The international community remains confronted with a continuous downward spiral into another cycle of widespread violence despite important efforts," he said.

Guterres warned that without urgent action "the stability of the entire region, and beyond, is in jeopardy, leaving millions of people at risk of violence," a development he described as a "disastrous scenario."

The vast Sahel region has turned into a hotbed of violent extremism and lawlessness since chaos engulfed Libya in 2011, the Islamist takeover of northern Mali in 2012 and the rise of Boko Haram in northern Nigeria.

Four US soldiers were killed this month in an ambush while on a joint patrol with Nigerien troops near the Mali border, an attack thought to be carried out by a regional affiliate of the Islamic State group.

- UN options -

The UN chief put forward four options to back the force, including setting up a United Nations support office in the Sahel and sharing resources from the 13,000-strong peacekeeping mission in Mali.

The report will undoubtedly be welcomed by France, which has been lobbying hard for UN backing for the Sahel force, but the United States has resisted calls for funding.

The estimated budget for the force's first year of operations was estimated at 423 million euros ($499 million), but so far only 108 million euros have been raised.

The G5 countries have pledged 10 million euros each, the European Union is giving 50 million and France eight million euros. A donors' conference will be held in December in Brussels.

Guterres said the risks of not supporting the Sahel force "vastly outweigh the risks of supporting it, given the magnitude of the challenges facing the Sahel region."

The UN chief stressed that there was a risk of human rights abuses during the counter-terror operations because many of the armed groups in Mali are entrenched in the population.

A UN presence, he argued, could help reduce harm to civilians.

UN Security Council ambassadors will travel to Mali, Burkina Faso and Mauritania from Thursday to meet with leaders and discuss plans for the deployment of the force.

The council is expected to discuss the report during a meeting on peace and security in Africa on October 30.

Source: AFP