Nigeria President Buhari army
President Muhammadu Buhari says new task force is likely to defeat terrorists by December. Getty

Nigerian President Muhammadu Buhari has said a new task force involved in the fight against terror group Boko Haram will defeat the insurgents by December.

The leader made the comment as he was visiting Benin, one of the countries involved in the offensive. Buhari previously visited Niger, Chad and Cameroon to strengthen the antiterrorism cooperation.

Who are Nigeria's Boko Haram terrorists?

Boko Haram (recently renamed Iswap) fights against Western influence in Nigeria and aims to impose its version of Sharia law in the country.

The group declared an Islamic caliphate in Gwoza, along the Cameroon border, in August 2014.

Boko Haram has raided several cities in the north of the country in a bid to take control of more land.

Three states − Adamawa, Borno and Yobe − have been under a state of emergency since May 2013, due to Boko Haram's attacks.

The group has killed more than 3,000 people since the beginning of 2015.

The five countries were already involved in a regional offensive against the terrorists which scored some goals since it was created in February. However, the Nigerian army announced that a new task force, expected to be more efficient, is ready to take over the fight.

The task force comprises some 8,700 soldiers from the five African nations and is headed by Major General Iliya Abbah, who previously conducted military operations in the Niger Delta.

Benin's President Thomas Boni Yayi announced the country would send 800 troops to join the new force and "permanently combat these outlaws", AFP reported. The announcement follows Cameroon's decision to send some 2,000 military reinforcements to the north of the country, near the border with Nigeria, to help fight the terrorists.

The Nigerian army recently freed some 178 people held captive by the terrorists, renowned for kidnapping civilians – mainly women and children – and forcing them to participate in terror attacks.