Nigeria's military on Monday said it had begun shifting the command centre for its battle against Boko Haram from the capital to the northeastern city of Maiduguri, following a directive from President Muhammadu Buhari.

Separately, Buhari met leaders of the G7 nations at a summit in Germany, and reaffirmed his pledge to crack down on the Islamists, while calling for greater regional and international cooperation.

The defence ministry later announced that service chiefs from the four nations on the frontline in the Boko Haram battle -- Chad, Cameroon, Niger as well as Nigeria -- would meet in Abuja on Tuesday for talks on joint operations.

Buhari revealed the headquarters shift in his inaugural speech on May 29, saying the insurgents would not be defeated until military command and control was transferred to the city at the heart of the uprising.

"A reconnaissance and advance team for the establishment of Military Command and Control Centre (MCCC) for Operation Zaman Lafiya for the fight against terrorism and insurgency has moved to Maiduguri," an army statement said.

"Zaman Lafiya" means "peace" in the Hausa language widely spoken in northern Nigeria.

- Advance team -

Army spokesman Sani Usman said the advance team was working to set up a fully functioning "forward command base" to coordinate the offensive against the Islamists, who are blamed for more than 15,000 deaths since 2009.

Boko Haram was founded in Maiduguri, Borno state's capital, more than a decade ago and the group has carried out scores of attacks there.

Addressing the conflict after he was sworn in, Buhari said "victory can not be achieved by basing the Command and Control Centre in Abuja...

"The command centre will be relocated to Maiduguri and remain until Boko Haram is completely subdued."

Analysts described the announcement as a shrewd move from former army general Buhari, who appears committed to intensifying the fight against Boko Haram.

At least 93 people have been killed in 11 suspected Boko Haram attacks since Buhari took office, highlighting the grave threat the group poses, despite recent gains by a four-nation offensive against the insurgents.

Nigeria, Cameroon, Chad and Niger launched a generally praised joint counter-insurgency operation in February.

The offensive has liberated large swathes of territory from Boko Haram control but there are signs of the insurgents regrouping.

- IS intelligence -

In bilateral talks at the G7, Buhari told French President Francois Hollande he wanted more intelligence help concerning Boko Haram's links to the Islamic State group in Iraq and Syria, a statement from his office said.

The Nigerian Islamists swore allegiance to IS in March.

While the extent of the ties between the two groups is unclear, Boko Haram has developed a more sophisticated media strategy in recent months, which some analysts attribute to IS guidance.

Buhari also asked Hollande for more intelligence about Boko Haram's "movements, training and sources of its arms and ammunition", as he designs his counter-insurgency strategy, the statement said.

France is seen as a key actor in maintaining the relationship between Nigeria and its northeastern neighbours, which are all former French colonies.

Buhari said he had already taken "concrete action to build a more efficient and effective coalition" and asked for further French support in solidifying the alliance.

- Regional force -

Nigeria said Tuesday's talks between defence chiefs from the four countries battling Boko Haram will centre on a multi-national force which has operated in the Lake Chad area since the late 1990s to combat smuggling, but which has become more important since the emergence of the militant group.

Buhari has said he expected a greater effort from this force. Several of the deadliest attacks in the uprising have targeted the Lake Chad region, notably in the Nigerian town of Baga.

Tuesday's meeting will focus on the strategy for the "modified version of the Multi-National Joint Task Force," as it plans to wade deeper into "the campaign against terror," Nigeria's defence ministry said.