Cameroon says 5 Boko Haram leaders arrested; dozens freed

French President Francois Hollande delivers a speech during the 2nd Regional Security Summit in Abuja on May 14, 2016.

Hammond met with key regional leaders to discuss what the global community can do to support Nigeria with its security issues.

Leaders from Benin, Cameroon, Chad and Niger beside French President Francois Hollande, high-ranking diplomats from the United States, Britain and the European Union are attending the summit.

The Nigerian military has occupied schools, transforming them into barracks or command centres.

Regional and Western powers gathered in Nigeria to discuss their war with Boko Haram, as the United Nations said the group posed a major threat to security in West Africa.

Earlier, the UN Security Council voiced its deep concern on "the alarming scale" of the humanitarian crisis caused by Boko Haram's activities in the Lake Chad Basin region.

The first regional summit on Boko Haram was held in Paris on May 17, 2014 as the worldwide community woke up to the threat posed by the group in the wake of its mass abduction of schoolchildren in Nigeria's Chibok town on April 14 that year.

Nigeria is seeking closer military cooperation to bring to an end almost seven years of violence, which has left at least 20,000 dead and displaced more than 2.6 million people in the northeast.

Boko Haram is one of the deadliest terror groups in the world.

Mausi Segun, a Nigeria researcher for Human Rights Watch, recently said those children remain missing.

This shouldin turn prevent boko haram from continuing to take advantage of its ability to move across borders.

Last year, the extremist group released a video pledging their official allegiance to ISIS.

"The Nigerian government and regional governments have to deal with the immediate challenge and the underlying elements, not timeframe", he said.

"By December the armed forces of Nigeria, Cameroun, Chad and Niger degraded boko haram and squeezed them into a small enclave of Sambisa Forest", President Buhari said.

They made the pledge while addressing the 2nd Regional Security Summit in Abuja at the weekend.

But he warned: "This terrorist group nevertheless remains a threat".

"This will help because if you defeat Boko Haram and you are not able to deal with the underlying problems, it may make some people to be extremists".

Countries hit by the violence needed to win "the hearts and minds of those terrorized by Boko Haram", Hammond said.