At least 15 people are dead after two female suicide bombers carried out the latest attack in Cameroon's far north, the government said Thursday, and another 42 people are wounded.

The attackers entered the town of Waza late Wednesday and one detonated explosives near a group of youths, Governor Midjiyawa Bakary said.

Nigeria-based Boko Haram extremists have been crossing borders to stage attacks in countries, including Cameroon, that contribute to a military force that seeks to eliminate the insurgency. The Islamic extremists have killed more than 20,000 people in their eight-year existence and abducted thousands of others.

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

The attacks in Cameroon's far north, the poorest part of the country, have been a factor in sending more than 13,000 Nigerian refugees who had fled Boko Haram back to their own nation since mid-April.

The suicide attacks, roadside bombings and raids on villages also have been "complicating humanitarian operations and subjecting civilians to persistent danger," the U.N. humanitarian agency said earlier this week.

In addition, the U.N.'s World Food Program has cut food assistance to almost 200,000 Nigerian refugees and displaced people by 25 percent since January because of lack of funding.

The Boko Haram-fueled crisis in northeastern Nigeria, which borders Cameroon, is part of what the U.N. has called the largest humanitarian crisis in more than 70 years, with millions facing hunger.