The leader of Nigerian militant group Boko Haram has appeared in a video stating that his men were behind the massacre in the northeastern town of Baga earlier this month.

"We killed the people of Baga," the man claiming to be Shekau in the video said. He added that the group killed the civilians "as our Lord instructed us".

The Islamic militant group reportedly killed over 2,000 in a massacre in the town, sparking international condemnation, while three female suicide bombers killed 23 people in separate incidents in the town of Potiskum and city of Maiduguri.

Amnesty International said that the massacre at Baga was the largest attack by the group in its five-year-long insurgency.

The video shows an arsenal of weapons allegedly stolen from a military base in a neighbouring town to Baga in their assault of the surrounding area.

The video could not be independently verified by IBTimes UK but AFP said that the video was a typical Boko Haram video with masked fighters surrounding Shekau.

According to the Council on Foreign Relations, the terror group killed over 10,000 people in 2014 as they continued to wage their insurgency against Nigerian authorities.

The terror group continue to carry out attacks in the country's majority-Muslim northern regions in their quest to establish an Islamic caliphate in similar fashion to that of the Islamic State [IS] in Iraq and Syria.