The International Criminal Court’s prosecutor, Fatou Bensouda, has condemned the escalation of “appalling levels of violence” in the North-East and warned she would prosecute members of any party responsible for war crimes and crimes against humanity.

Bensouda said her office is continuing a preliminary examination into allegations that Boko Haram extremists are killing large numbers of civilians, using girls and boys to participate in the conflict and forcing massive numbers of people from their homes.

She also warned the Federal Government of its obligation to prosecute crimes that “deeply shock the conscience of humanity.”

“No one should doubt my resolve, if need be, to prosecute those individuals most responsible for war crimes or crimes against humanity,” Bensouda said in a statement from the court’s headquarters in The Hague on Tuesday.

Boko Haram has increased the ferocity and tempo of its attacks in recent weeks, with international outrage over reports that as many as 2,000 civilians may have been systematically slaughtered in a January 3, 2015 attack on Baga town and the military base at the border with Cameroon.

The sect had also increased attacks on Cameroon, raising fears that the conflict is spreading and prompting the country to deploy troops to defend its borders with Nigeria.

Niger’s foreign minister, Bazoum Mohamed, told a meeting, on Tuesday, of the Economic Community of West African States to discuss a collective response to Boko Haram that the Islamist militants no longer are a Nigerian problem but threaten the security of the region.

Chad on Sunday deployed troops to fight Boko Haram in northern Cameroon, and Cameroon said more than 10,000 of its citizens are fleeing border regions following cross-border attacks.

No fewer than 140 schools have been shut in Cameroon following the Boko Haram attacks on border towns and villages.

The International Organization of Migration said on Tuesday that more than 1 million people are displaced in North-East Nigeria, adding that over 100,000 have fled to Niger, threatening a regional humanitarian crisis.