Divisions in Boko Haram have emerged with the appointment of a new leader who was criticized by the group's long-time military commander.

A weekly magazine published by the Islamic State called al-Naba announced the promotion of Abu Musab al-Barnawi from being the group's spokesperson to its new head. The magazine did not mention the former leader Abubakar Shekau.

Shekau, who led Boko Haram since 2009, released a 10-minute audio clip on YouTube criticizing al-Barnawi's supposed opinion about living peacefully among non-Muslims.

"I am against the principle where someone will dwell in the society with the infidels without making public his opposition or anger against infidels," Shekau said in the local Hausa language.

The audio clip was removed from YouTube shortly after it was uploaded.

Shekau used to release frequent videos till March where he would be seen holding heavy weaponry and mouthing hateful speeches against the nation of Nigeria and the West. The absence of videos in months had led to speculations that he was not alive or wounded.

A video released by ISIS in April had said that Shekau was not dead and was not replaced from his position.

In the recent audio clip, Shekau said that he was the organization's leader and that al-Barnawi was only trying to cause divisions in the group.

According to security analysts, he appeared to be anxious in the clip while voicing his opposition of al-Barnawi.

"Of course, he's so confused and it's a sign, he [Shekau] was showing sign of weakness," said Khalid Aliyu, the secretary-general of Jama'atu Nasril Islam, an umbrella body of Islamic organizations in Nigeria. "I think it's a sign of the end of the whole saga - that is one - two, it's a sign of a defeat also. It's also a sign of loss of power and control of the insurgency itself, therefore it shows a crack in the organization of the insurgency."

Experts said that the attempted shift in power may cause conflicts in the organization.

"There will be clash over leadership if it is true that Barnawi is the new leader and Shekau is saying I am still the authority, you know. There will be clashes. They will be fighting each other," said Bulus Mungopark, a member of a Nigerian vigilante group, a key ally of Nigerian military.

Security Analyst from northern Nigeria, Shehu Umar, told DW that the split in leadership was an opportunity for the government to further decimate the group. "This is a golden opportunity for Nigerian intelligence," he said. The group has suffered consistent losses over the last 18 months, and is being pushed back.

Boko Haram killed 20,000 people and displaced about 2.6 million people in its seven-year insurgency in northeast Nigeria.