More than 1.6million believed to have fled from Nigeria in past five years

The audacity and frequency of their cross-border attacks is getting worse

Militants have killed over 2,000 and kidnapped 80 people in recent weeks

Boko Haram attacks have forced more than 10,000 panic-stricken Cameroonians to flee from the border regions with Nigeria's Borno State.

In recent weeks, the Islamic militant group has massacred over 2,000 people in two north-eastern towns - before kidnapping dozens of people during an attack on Mabass village.

Abubakar Shekau, the man who claims to be its leader, has previously threatened to target Cameroon unless it scrapped its constitution and embraced Islam.

The insurgents have looted food and livestock on the border, which has raised fears that a food shortage and humanitarian crisis is imminent, according to a government spokesperson.

Threat: In a video released on January 5, Boko Haram's supposed leader Abubakar Shekau (pictured) promised to strike Cameroon with the same ferocity with which it has terrorised Nigeria

Destruction: Boko Haram killed over 2,000 people in a brutal attack on the northern towns of Baga and Doron Baga (pictured) on January 3

Retaliation: On Friday, dozens of Chadian tanks headed out of the capital towards Cameroon to help fight Nigeria's Boko Haram insurgents

Turmoil: A map showing Nigeria and the location of Baga which was devastated by brutal Boko Haram fanatics last week

The 10 schools deserted after Sunday's attack on Mabass follow around 140 that have already shut their doors since the assaults began bleeding over the border, the country's Minister of Education has said.

The government is trying to accommodate affected students but Bernadette Appi, a primary school teacher in Maroua, says safer schools have a 'moral obligation' to admit fleeing students.

These latest attacks highlight the growing regional threat posed by Boko Haram, which has sought to impose strict Shariah law in Nigeria - the continent's most populous nation.

It has now seized villages along a 155-mile stretch of land along the Cameroon-Nigeria border.

Boko Haram Islamist fighters from Nigeria kidnapped around 80 people on Sunday - many of them children.

They killed three others in their most audacious cross-border attack on villages in northern Cameroon, army and government officials said. They believe around 30 people managed to escape.

Troops from Chad began to arrive in the country on the same day, to support their fight against the militants.

Neighbouring countries are being increasingly drawn into Nigeria's five-year battle with the extremists, which has killed thousands and driven 1.6million people from their homes - and into neighboring Cameroon, Niger and Chad.

Officals believe Boko Haram has been recruiting fighters in all three countries.

This latest atrocity comes as the International Criminal Court's prosecutor condemned the 'appalling levels of violence' in Nigeria and warned she would prosecute members of the party responsible for crimes against humanity.

Fatou Bensouda said her office is continuing a preliminary examination into the allegations that Boko Haram extremists are killing large numbers of civilians - as well as manipulating boys and girls into fighting for their cause.

Refugees: Baby Lurky's (pictured) family are among the 1.6million to flee Nigeria during their 5-year battle with Boko Haram

Homeless: A displaced mother and her daughters, who fled Boko Haram violence in the northeast region of Nigeria

Evacuation:One primary school teacher believes safer schools have a 'moral obligation' to take in fleeing students (pictured)

Response: Nigerian president Goodluck Jonathan (pictured) has promised that all areas of Nigeria under the control of the terrorists would be recaptured soon

She also warned Nigeria's government of its obligation to prosecute crimes that 'deeply shock the conscience of humanity'.

She added: 'No one should doubt my resolve, if need be, to prosecute those individuals most responsible for war crimes or crimes against humanity.'

Both Boko Haram and the Nigerian military have been accused of the summary executions of hundreds of civilians in the 5-year uprising, in which over 10,000 people died only last year.

Boko Haram has increased the ferocity and deadliness and of its attacks in recent weeks. On January 3, the group killed more than 2,000 civilians and razed 3,700 buildings to the ground in the towns of Baga and Doron Baga.

Survivors of the attack recall having to flee over the dead bodies of people who were 'killed like insects'.