His redeployment to an unspecified post follows a string of attacks by the insurgents, including the killing of at least 50 people in a mosque last month.

No official reason was given for Maj Gen Ibrahim Attahiru's removal.

Army chief Gen Tukur Buratai gave him a deadline in July to deliver Boko Haram leader Abubakar Shekau dead or alive within 40 days.

At least 20,000 people have been killed and thousands more abducted since Boko Haram launched its insurgency in north-eastern Nigeria in 2009.

• Africa Live: More updates
• Why some Boko Haram 'wives' choose to go back
• Who are Boko Haram?

President Muhammadu Buhari took office in May 2015 with a pledge to beat back the militants.

About seven months later, he declared that Boko Haram had been "technically defeated" after the army recaptured most territory that had fallen to it.

However, Boko Haram has continued carrying out bomb and gun attacks in the north-east.

In July, more than 40 people died during a military operation to free people who had been ambushed in a convoy by the militants.

The dead included soldiers and an oil exploration team.

Maj Gen Attahiru Ibrahim was appointed to lead the offensive against Boko Haram in the north-east in May this year.

He has been replaced with another general, Nicholas Rogers, who led a special military and police force to tackle ethnic clashes in the volatile central region.

Boko Haram at a glance

• Founded in 2002
• Official Arabic name, Jama'atu Ahlis Sunna Lidda'awati wal-Jihad, means "People Committed to the Propagation of the Prophet's Teachings and Jihad"
• Initially focused on opposing Western education
• Launched military operations in 2009 to create Islamic state
• Designated a terrorist group by US in 2013
• Declared a caliphate in areas it controlled in 2014
• Most territory now recaptured by army