Boko Haram has killed nearly 400 people in Nigeria and Cameroon since April.
The terror group based in northeastern Nigeria has increased its use of suicide bombers, often using young women and girls to carry and detonate explosives in crowded areas.
Amnesty International said at least 381 civilians have been killed in five months.
The surge in attacks has claimed double the amount of lives than in the previous five months.
Amnesty said at least 223 people have died in Nigeria since April, while at least 158 civilians have been killed at the hands of Boko Haram in Cameron in the same period.
More than one suicide attack has been carried every week out in Nigeria and Cameroon since April.
The deadliest attack took place in Waza in Cameroon on July 12 when 16 civilians were killed and at least 34 were injured after a young girl was forced to detonate a bomb in a busy video game centre.
Alioune Tine, Amnesty International’s director for West and Central Africa, said: “Boko Haram is once again committing war crimes on a huge scale, exemplified by the depravity of forcing young girls to carry explosives with the sole intention of killing as many people as they possibly can.”
Mrs Tine also called on governments in Nigeria and Cameroon to “take swift action to protect them from this campaign of terror.”
At least 20,000 people have been killed in violence caused by Boko Harm and more than 2.6 million people have been left homeless since 2009.
Fighting has devastated farmland, resulting in the starvation of more than five million people.
The violence has also forced thousands of children to stop attending school.