Unidentified assailants killed 19 people and wounded 13 in an attack on and around the town of Arbinda in northern Burkina Faso on Sunday, the government has said.

Hundreds of people have died in violence over the past months and more than 150,000 have been forced to flee as armed groups have spread across the arid Sahel region.

Once a pocket of calm in the Sahel, Burkina Faso has suffered a spillover of violence from neighbouring Mali, where an attack on a village on Sunday left at least 95 people dead and more than a dozen missing.

Deteriorating security prompted the government to declare a state of emergency in several northern provinces bordering Mali in December, which was extended by six months after armed individuals attacked civilians in Arbinda’s Soum province.

Burkina’s armed forces have launched a search operation across the area targeted by Sunday’s attack, the government said late on Monday.

Burkina Faso, which has a history of religious tolerance, has been beset by a rise in attacks as groups based in neighbouring Mali seek to extend their influence over the Sahel, the arid scrubland south of the Sahara.

About 60 percent of the country’s population is Muslim, roughly 25 percent is Christian, and the rest follow indigenous religions.

The raids began in 2015 in the north before targeting the capital Ouagadougou and other regions, notably in the east, and have been attributed to a number of armed groups, including the Group to Support Islam Muslims (GSIM) and Islamic State in the Greater Sahara.

The town of Arbinda has witnessed a spate of violence in recent months despite increased security operations.

In April, 62 people were killed in attacks and ensuing ethnic clashes, and four people travelling by car were ambushed and killed.

In March, researchers reported a “massive spike” in deadly violence in recent months across the Sahel.

“Conflict in Mali, Niger and Burkina Faso is a major driver of the escalation and civilians have faced the brunt of violence,” the Armed Conflict Location and Event Data Project (ACLED) reported in March.

From November 2018 to March 2019, ACLED reported that fatalities in Burkina Faso targeting civilians rose by a startling 7,028 percent compared with the same period last year. 499 fatalities were recorded from 124 events.

The rising tide of intercommunal violence in the Sahel shows few signs of stopping, the report noted.

In neighbouring Mali, an unprecedented massacre in March left more than 130 people killed in an attack on a Fulani village.

France has deployed 4,500 troops in Mali, Burkina Faso, Niger and Chad in a mission code-named Barkhane to help local forces push out fighters.