Lagos (AFP) — Videos have emerged purporting to show members of a Nigerian Islamist sect preparing for suicide attacks, including a young man said to be responsible for last month’s bombing of UN headquarters.

The two videos obtained by AFP are said to be from the sect known as Boko Haram and come as concern intensifies over whether it has formed links with outside groups such as al-Qaeda’s north African branch.

The voice said to be Shekau’s calls the UN headquarters a “forum of all the global evil,” while also offering praise for Osama bin Laden.

The video focusing on the UN bombing, which killed at least 23 people and was among the deadliest targeting the world body, is more than an hour and 15 minutes long.

A soft-spoken, 27-year-old smiling man said to be the UN bomber pleads with his family to understand his actions, and a vague warning is sent out to “Obama and other infidels.”

During much of his time on the video, he holds an AK-47 while two others lean against the wall. Two gas canisters are on the floor at his feet.