A campaign “on all fronts” is needed to tackle the Islamist militant group Boko Haram, Nigeria’s president has said.
President Muhammadu Buhari told his regional counterparts that this includes better intelligence sharing to stop the flow of money and weapons.
The leaders are in Nigeria’s capital, Abuja, to re-launch a joint military force to confront the jihadists.
The six-year Islamist insurgency in north-east Nigeria has also drawn in neighbours Chad, Cameroon and Niger.
Thousands of people have been killed and hundreds kidnapped.
Mr Buhari said that Boko Haram has the region in a “vicious stranglehold” and the “dastardly crimes against our people by the insurgents” have emphasised what the nations have in common.
At his inauguration in May, Mr Buhari vowed that he would tackle Boko Haram “head on” and also pledged to work with his neighbours.
Calling this meeting at short notice is another sign that ending the Boko Haram insurgency is the number one priority for Nigeria’s new president, the BBC’s Nigeria reporter Will Ross says.
Mr Buhari says fighting Boko Haram should include limiting the group’s capacity to access funds and weapons, which is where better intelligence gathering should help.
Chad, Cameroon and Niger have been assisting Nigeria recapture territory from the insurgents, but a plan to create a large joint military force had stalled.
Nigeria has pledged $100m (£64m) to help create the regional force which will be based in the Chadian capital, N’djamena.
It had been suggested a different country would take over the command of the regional force every six months.
But President Buhari said it would be more effective if Nigeria retained the command throughout the conflict.
During the two weeks that President Buhari has been in office, more than 100 people have been killed in gun attacks and bomb blasts blamed on Boko Haram.