Nigeria plans to withdraw some of its troops from Mali because they are needed back home, where the country is battling a deadly Islamist insurgency, officials said Thursday.

It was not clear how many troops would be pulled from the troubled west African nation, where Nigeria currently has some 1,000 troops, a Nigerian military source said.

Ivory Coast President Alassane Ouattara, current chair of the 15-nation West African bloc ECOWAS, told reporters the withdrawal was because Nigeria needed its soldiers back home.

"It's because of the domestic situation," Ouattara said after an ECOWAS summit in the Nigerian capital Abuja.

"I received a letter from the president. Nigeria needs some of its people. They are not withdrawing everyone. They are withdrawing part of the troops. A good part of the troops are going to be there."

However, the military source said troops would pull out because the country felt "shabbily treated" under the new UN force in Mali.

A Nigerian commanded the previous African-led force in the country, but the UN mission is being headed by a Rwandan. Nigeria, Africa's most populous nation and largest oil producer, has the biggest military in west Africa.

"Nigeria feels shabbily treated ... when it became a UN outfit," the military source said on condition of anonymity because he was not authorised to discuss the matter publicly.

"...A non-Nigerian was appointed as force commander while we are putting so much into the mission. So we think we can make better use of those people at home than to keep them where they are not appreciated."

He added that "it is not all of them that will be withdrawn," without providing specifics.

The UN mission integrates more than 6,000 west African soldiers into its ranks and is charged with ensuring security during and after July 28 elections in Mali.

It is to grow to 11,200 troops, plus 1,400 police, by the end of the year.

French forces intervened in Mali in January to push out Islamist rebels who had seized the north. The UN deployment has allowed France to start withdrawing most of its 4,500 troops.

Nigeria approved the deployment of 900 troops with the capacity to increase to 1,200 under the previous African-led force.

Nigeria's military has been stretched thin back home.

Violence linked to an insurgency by Islamist extremist group Boko Haram, mainly in Nigeria's north, has left some 3,600 people dead since 2009, including killings by the security forces.