Boko Haram increasingly uses girls and young women to carry out such attacks.

At least eight people were killed on Monday when a female suicide bomber detonated at a mosque in northeastern Nigeria.

A spokesman for a civilian self-defence force in Maiduguri city said the bomber was being chased by local security workers and ran into the middle of worshippers and exploded. At least 13 people were wounded.

The mosque collapsed in the blast. Police did not immediately comment. The Nigeria-based Boko Haram extremist group often targets Maiduguri, where its eight-year insurgency began.

Two girls wanted to attack

“There were two girls that wanted to attack the mosque but one of them got stuck in barbed wire in the ditch dug near the area, but the second one escaped and began to run as our operatives there began to chase after her,” said spokesman Danbatta Bello with the Civilian-JTF self-defence force.

“She rushed to the mosque and detonated the second bomb.” The first girl blew up where she was trapped, Mr. Bello said.

Two others shot dead

Two other female suicide bombers were shot dead in Maiduguri around the same time the mosque was attacked, he said.

Boko Haram has increasingly used girls and young women to carry out attacks. Some young women who escaped the extremist group have said girls are drugged and forced to carry out suicide missions.

Nigeria’s government late last year declared that Boko Haram had been “crushed” but deadly attacks continue.

Scourge surge and spillover

The Islamic extremist group’s insurgency has killed more than 20,000 people, abducted thousands of others and spilled over into neighboring countries.

Northeastern Nigeria is part of what the United Nations has called the world’s largest humanitarian crisis in more than 70 years, with the World Food Program estimating that more than 4.5 million people in the region need emergency food assistance. Boko Haram’s insurgency has disrupted both agriculture and markets.