Nigeria on Saturday hosts talks on Boko Haram with regional and Western powers, hoping for closer military cooperation and help with tackling the conflict's dire humanitarian fall-out.
The leaders of Benin, Cameroon, Chad and Niger are due to attend, with French President Francois Hollande, US Deputy Secretary of State Antony Blinken and Britain's foreign minister Philip Hammond.
Delegations from West African and Central African blocs, plus the European Union have also been invited.
Nigeria's President Muhammadu Buhari, who has vowed to defeat Boko Haram before the end of his first year in office this month, was scheduled to meet Hollande at the presidential villa in Abuja.
Both countries recently signed an agreement on closer military cooperation, including in intelligence sharing, and France is keen to help implement a regional solution to the Islamist insurgency.
Paris has traditionally concentrated on its former colonies surrounding Nigeria and sees itself as well-placed to help closer ties and longer-term economic development in the troubled region.
The summit -- two years after a first such high-level gathering in Paris -- comes as Nigeria's military pushes deep into Boko Haram's Sambisa Forest stronghold after recapturing swathes of territory in the northeast.
The army has portrayed the Islamist militants as in disarray, but there have been warnings against any premature declaration of victory.
Blinken told reporters in Abuja on Friday that Washington, which is flying surveillance drones over northeast Nigeria from northern Cameroon, did not see Boko Haram as defeated.
But he conceded "they have been degraded" and noted its links to the Islamic State group, as well as reports of Boko Haram rebels fighting alongside their jihadi counterparts in lawless Libya.
"We are extremely vigilant about these connections... this is again something we are looking at very, very carefully because we want to cut it off," he added.
The formal deployment of a long-awaited 8,500-strong regional force comprising troops from Nigeria, Benin, Cameroon, Chad and Niger is expected to be high on the agenda at the talks.
The African Union-backed force was supposed to have been on the ground in July last year.
Plugging gaps and improving coordination between armies operating largely independently is seen as vital, with Boko Haram now thought to be in remote border areas on and around Lake Chad.
Lake Chad forms the border between Nigeria, Cameroon, Chad and Niger.
There will also likely be discussion on tackling the humanitarian effects of the conflict, which has killed some 20,000 people and forced more than 2.6 million from their homes since 2009.
The government of Borno state -- the worst-hit by the violence -- has said the displaced face a "food crisis" and $5.9 billion (5.1 billion euros) was needed to rebuild shattered infrastructure.
US ambassador to the UN Samantha Power, who visited northeast Nigeria and northern Cameroon last month, said 9.2 million people in the wider region were affected by the conflict.