The senior officers sacked by President Muhammadu Buhari had been appointed in January 2014 by his predecessor Goodluck Jonathan when he replaced other service chiefs over their failure to halt the Boko Haram insurgency.

There has been a rapid increase in suicide bombing in attacks in recent weeks, not only in Nigeria but also in neighboring countries. Nigerian conflict resolution analyst Anminu Gamawa told DW's Hausa service that this had shown that "there is a need for a new approach, a need for new people with new ideas and that could not happen if he were to retain the service chiefs appointed by his predecessor."

Buhari, who has been in power for less than seven weeks, made the announcement on Monday (13.07.2015) as details emerged of a suspected Boko Haram attack on two villages, Kalwa and Gwollam, in Borno state on Friday in which dozens of people were killed and houses were burnt down.

Cameroon suicide bombing

The militants also launched their first suicide bomb attack in neighboring Cameroon when two women blew themselves up. DW's correspondent in Cameroon, Moki Kindzeka, said the dead included ten civilians, one Chadian soldier and the two bombers. The attack took place near the military base in the border town of Fotokol.

Last April Cameroon said it had started a mass education program urging young people to reject the "Islamic State" ideology which Boko Haram was seeking to spread in the country.

Cameroonian President Paul Biya called for calm after the suicide bombing, but one Cameroonian resident in the capital Yaounde told DW "I am quite terrified."

Chad was also targeted on Saturday when a suicide bomber detonated an explosive device in a crowded market in the capital N'Djamena killing 15 people.

Balance between Muslim north and Christian south

It was against this background that Buhari appointed Major General Tukur Yusuf Buratai as the new army chief of staff and Major General Babagana Monguno as the new national security adviser. Both are from Borno state.

The new defense chief is Major General Abayomi Gabriel Olonisakin and the new navy chief Is Rear Admiral Ibok-Ete Ekwe Ibas. They are from the south of Nigeria. The chief of defense intelligence, Air Vice Marshal Morgan Monday Riku, is from the Middle Belt and the chief of air staff, Air Vice Marshal Sadique Abubakar, is from Bauchi state in the north.

By distributing the appointments evenly between Nigeria's mainly Muslim north and its mainly Christian south, Buhari has evidently sought to avoid allegations of partisanship leveled against his predecessor. Jonathan had named Christians to all but one of the positions.

Rights abuses

Gamawa said Nigerians had been expecting Buhari to make changes at the top of the military. He welcomed the appointment of General Buratai, currently commander of the anti-Boko Haram multinational task force which is located in Chad. "He is very competent, knowledgeable and a good leader" Gamawa said.

But Nigeria's military has not just been criticized for its failure to defeat Boko Haram. It is also burdened by the opprobrium of repeated allegations of rights abuses.

In June 2015, rights group Amnesty International accused Nigeria's military of systemic human rights abuses and the deaths of 8,000 prisoners in military custody. Buhari has promised to investigate Amnesty's allegations. Hundreds of soldiers are being court-martialed for alleged cowardice and desertion.

Atrocities committed by the Nigerian military have hampered help from the United States in counter-insurgency efforts because of laws that prevent the US from providing certain arms to the governments of armed forces accused of gross human rights abuses.