A young girl detonated a suicide bomb in a mosque in northern Cameroon early Wednesday, killing at least five worshippers and wounding others.

The girl, about 12, entered the Sanda-Wadjiri mosque in Kolofata after the first call to prayer, said the governor of the Midjiyawa Bakary region, near the Nigerian border.

No one claimed responsibility for the attack, but Boko Haram militants have been waging a war to establish an Islamist state in the region that includes Nigeria, Chad, Niger and Cameroon.

The terrorist organization has also taken to more frequently using women and children as suicide bombers.

Amnesty International said last week that more than 400 people have been killed in Nigeria and Cameroon since April, more than double the number killed in the previous five months.

At least 20,000 people have been killed in violence since 2009 and more than 2.6 million people have been left homeless.