Twenty-three soldiers were killed in a Boko Haram attack in southwestern Chad on Friday, March 22, a military official told AFP.

“Boko Haram elements attacked the Chadian army position at around 1 a.m., killing 23 troops,” the official said.

The attack, which took place in Dangdala, on the northeastern bank of Lake Chad, appears to be the deadliest attack on the Chadian military by Boko Haram.

The assailants crossed over from Niger before launching the raid and “made off with military equipment,” the source said.

It is unclear which faction of Boko Haram carried out the attack, but Islamic State West Africa province is the dominant insurgent force in the Lake Chad area.

Civilians killed in Niger

In the Diffa region of southeastern Niger, meanwhile, eight civilians were killed late Thursday in a Boko Haram attack in Karidi, which is in Gueskerou district, a local official told AFP Friday.

ActuNiger reported the attack occurred in the village of Dewa Kargueri, around 7 km southwest of Gueskerou commune and began at around 9:30 p.m.

According to the ActuNiger report, militants attempted to destroy a bridge in the Diffa region on Wednesday.

Diffa in Niger and neighboring Borno state in Nigeria have seen a number of attacks in recent weeks, as the Multinational Joint Task Force, which comprises troops from Chad, Cameroon, Niger and Nigeria, conducts Operation Yancin Tafki against Boko Haram around Lake Chad.

Islamic State has made a slew of claims of attacks on both sides of the Niger-Nigeria border, but many have not been confirmed by official sources and the claims are at times contradictory.

On March 9, seven police and 38 militants were killed near Gueskerou, according to a government toll. The MNJTF said in a statement that “27 terrorists” were killed.

Islamic State claimed fighters from its West Africa province affiliate killed 30 soldiers in a March 9 attack on a military base in Toumour in the Diffa region. Toumour is around 30 km (19 miles) northeast of Gueskerou, and it is unclear whether the ISIS statement referred to the Gueskerou incident or to another attack.

Across the border in Nigeria on March 12, aircraft from Nigeria, Niger and Cameroon supported by MNJTF ground troops killed 33 ISWA militants around Tumbun Rego and Arege, the regional force said.

ISIS claimed an ISWA militant carried out a suicide car bomb (SVBIED) attack in Arege on March 13, although its al-Naba magazine later said that attack was carried out on March 14.

ISIS claimed ISWA militants fired three Grad rockets at Diffa airport on March 14. ActuNiger reported that ISIS claimed that an ISWA militant carried out a SVBIED attack in Toumour the same day and that local and security sources confirmed that it occurred. ISIS’s Al-Naba magazine put the Grad attack on March 15 and the SVBIED attack on March 13. ISIS later published images of what it said were the Grad launches.

ISIS claimed ISWA killed five soldiers attached to the MNJTF during clashes on Thursday in Monguno, in Nigeria’s Borno state. Via its Amaq propaganda agency, ISIS claimed three of the dead were Chadian and two Nigerian. It also claimed that four “mortar shells” were fired at Nigerian army positions in the town on Thursday, and six were fired at positions in Malam Fatori on Wednesday.

ISIS further claimed via Amaq that 10 soldiers were killed on the Monguno-Gajiram road on Thursday.

Boko Haram’s bloody insurgency began in northeastern Nigeria in 2009 but has since spread into neighboring Niger, Chad and Cameroon, prompting a regional military response. Some 27,000 people have been killed and two million others displaced, sparking a dire humanitarian crisis in the region.

Boko Haram split into two factions in mid-2016. One led by long-time leader Abubakar Shekau is notorious for suicide bombings and indiscriminate killings of civilians. Shekau pledged allegiance to ISIS leader Abu Bakr Al-Baghdadi in March 2015, but ISIS central only gives formal backing to the other faction, which is known as Islamic State West Africa province.

The ISWA faction, which largely focuses on attacking military and government targets, was led by Abu Mus’ab Al-Barnawi, but earlier this month, audio recordings revealed that ISIS appointed Abu Abdullah Idris bin Umar also known as Ibn Umar al-Barnawi as leader. ISIS has not yet made a public statement confirming the change.

With reporting from AFP