ABUJA (Reuters) - Nigeria’s military is “ransacking” territory it said it has recaptured from Boko Haram in recent months in a search for its elusive leader, the country’s defense minister said on Tuesday.

The Nigerian military has said on multiple occasions that it killed Abubakar Shekau, leader of one of two branches of the jihadist group, only for the announcement to be swiftly followed by video denials from someone saying he is Shekau.

“He is on the run so he may be hiding in one of the enclaves of Sambisa forest,” Mansur Dan Ali, minister of defense, told reporters in Abuja.

“We shall be patrolling and ransacking that forest for the whereabouts of Shekau,” said Ali.

Earlier this month a man identifying himself as Shekau appeared in a video in which he claimed responsibility for a spate of bombings in and around the northeastern city of Maiduguri.

Large areas of the northeast, particularly in Borno state, remain under threat from Boko Haram as suicide bombings and gun attacks have increased in the area since late last year.

Ali said the military was committed to finding Shekau.

“We will not relax, we are on him,” he said.

Boko Haram split last year, with one faction led by Shekau operating from the Sambisa Forest and the other, allied to Islamic State and led by Abu Musab al-Barnawi, based in the Lake Chad region.

Nigeria’s army said in December it had pushed Boko Haram out of its Sambisa forest stronghold in an operation to reclaim territory lost to the Islamist insurgency since 2009.

The militant group had controlled a swathe of land in northeast Nigeria around the size of Belgium at the end of 2014 but was shifted from most of that territory early last year by Nigerian troops, aided by soldiers from neighboring countries.

Boko Haram has killed more than 15,000 people and displaced more than two million during its seven-year insurgency to create an Islamic state governed by a strict interpretation of sharia law in Africa’s most populous nation.