At least 15 people were killed on Monday when suicide bombers attacked an aid distribution point in northeast Nigeria, in the latest suspected strike by Boko Haram insurgents against civilians.

The blasts occurred in the Konduga area, about 40 km from the Borno state capital, Maiduguri, both of which have been repeatedly targeted by the jihadist group.

On August 16, at least 28 people were killed and more than 80 injured when three female suicide bombers detonated their explosives outside a camp for displaced persons in Konduga.

A rescue worker said the first blast on Monday happened at 11:10 am in the village of Mashalari. “[It] killed 15 people and left 43 others injured,” he told AFP.

“It happened during aid distribution by an NGO, when people had gathered to receive donations,” he said, speaking on condition of anonymity.

“Twelve minutes later, another bomber struck, but luckily only she died.”

The rescue worker said both bombers were women but did not specify which NGO was distributing aid.

Northeast Nigeria is in the grip of a humanitarian crisis caused by the Islamist Boko Haram insurgency, which has left at least 20,000 people dead and displaced more than 2.6 million since 2009.

The violence has devastated farming, leading to chronic food shortages and leaving hundreds of thousands of people on the brink of starvation and dependent on aid agencies for help.

Babakura Kolo, from the Civilian Joint Task Force, a militia assisting the military with security against Boko Haram, confirmed the rescue worker’s account.

“We have dispatched out team to the scene,” he said.

Nigeria’s military and government maintains that Boko Haram is a spent force as a result of a sustained counter-insurgency campaign over the last two years.

But continued attacks, particularly in hard-to-reach rural areas of Borno, suggest claims of outright victory are premature.

This month, jihadists fired a rocket-propelled grenade into a camp for the internally displaced near the border with Cameroon, killing seven.

Amnesty International says Boko Haram attacks since April have killed nearly 400 people in Nigeria and Cameroon —— double the figure of the previous five months.

The UN children’s fund said last month that 83 children had been used as suicide bombers this year, four times as many as in all of 2016.