The Sahel is facing an unprecedented wave of violence, with more than 4,000 deaths reported last year, and a bloody start to 2020.

The number of attacks have increased fivefold in Burkina Faso, Mali and Niger since 2016, United Nations figures have revealed.

Mohamed Ibn Chambas, the UN’s envoy for the fragile region on the southern rim of the Sahara, said it had experienced “a devastating surge in terrorist attacks against civilian and military targets”.

In Burkina Faso, the number of deaths rose from about 80 in 2016 to more than 1,800 in 2019.

On Tuesday, authorities in Ouagadougou, the capital, said dozens of civilians had been killed in the latest attack by suspected Islamic militants on a village market in the northern province of Sanmatenga.

Chambas told the UN security council earlier this month that the “devastating surge in terrorist attacks against civilian and military targets” would have alarming humanitarian consequences in the region and was set to spread.

“Most significantly, the geographic focus of terrorist attacks has shifted eastwards from Mali to Burkina Faso and is increasingly threatening west African coastal states,” he said earlier this month.

European officials are worried the Sahel is close to a tipping point that could see an irreversible slide into violent chaos that will strengthen extremist groups and send a new wave of migrants to Europe.

Extremist violence in the Sahel surged after a coalition of Islamists and local separatist tribesmen took control over much of northern Mali in 2012.

A seven-year campaign led by French troops, the deployment of hundreds of US special forces, massive aid for local militaries and a billion dollar-a-year United Nations peacekeeping operation have been unable to decisively weaken the multiple overlapping insurgencies in the region and security has continued to deteriorate.

Many of the bloodiest recent attacks have been attributed to an Isis affiliate, Islamic State in the Greater Sahara (ISGS).

In November, two attacks claimed by the ISGS on military bases in Mali, at Tabankort and Indelimane, claimed the lives of 92 soldiers. In December, the group claimed responsibility for the killing of 42 people – 35 of them civilian – in Arbinda in Burkina Faso. More than 170 soldiers have died in two recent ISGS attacks in Niger.

European security officials believe the claims of responsibility by the ISGS are credible, though the group frequently exaggerates its capabilities.

It is not clear who was responsible for this week’s attack in Burkina Faso, though Islamic militants are active in the area.

Chambas said attacks were often “deliberate efforts by violent extremists to capture weapons and trafficking routes”.

The ISGS has adopted tactics pioneered by the al-Qaida affiliate al-Shabab, which has been fighting foreign and national forces in Somalia for more than a decade. Attacks are launched by dozens of jihadists arriving on motorbikes who overrun often scant defences after cutting off the camp’s communications and pounding the site with mortars. They then kill as many soldiers as possible and then disappear before the army can fully respond.

“The latest attacks seem to show that the group has acquired skills in command, control and coordination that it didn’t have before, with group leaders able to carry out major operations,” a French military source told Reuters news agency.

The group’s rapid expansion in the Sahel will not compensate strategically for the loss of its heartland in Iraq and Syria, nor the death in October of its leader, Abu Bakr al-Baghdadi, but will boost morale among its beleaguered fighters and help attract new recruits.

It will also underline the continuing primacy of Islamic State in its long-running rivalry with al-Qaida, the older group from which it split six years ago.

Analysts say the ISGS, like other jihadist groups in the Sahel, uses “ad hoc” fighters to beef up its ranks, with up to 70% of the force launched against military bases hired just for the operation from local communities. Many are poachers, criminals or traffickers who are paid with cash, weapons or ammunition.

The hard core of ISGS is probably no more than 200- or 300-strong, specialists say. French forces total 4,500 and there are more than 13,000 UN peacekeepers.

Chambas said terrorism, organised crime and intercommunal violence were often intertwined, especially in peripheral areas where a state’s presence was weak where “extremists provide safety and protection to populations, as well as social services in exchanged for loyalty”.

The rise in violence comes amid reports that the US is likely to reduce its military presence in the Sahel, as it refocuses on great power rivals as a more significant threat than terrorism.

The US currently has thousands of troops in the region and recently opened a major $100m air base in Niger.

The prospect of many of its forces withdrawing from the region has dismayed many actors. A small detachment of British troops is due to deploy later this year to Mali as part of the UN peacekeeping force there.