A radical Muslim group in Nigeria, Boko Haram, has claimed responsibility for bombings and church attacks that killed at least 80 people on Christmas Eve.

"O Nations of the World, be assured that the attacks in Suldaniyya [Jos] and Borno on the eve of Christmas were carried out by us, Jama'atu Ahlus-Sunnah Lidda'Awatu Wal Jihad [Boko Haram], under the leadership of Abu Muhammad, Abubakar bin Muhammad Shekau," a statement posted on the group's website read.

Initially, authorities set the death toll at 38. But on Monday, Daniel Gambo of the Nigerian emergency management agency revised the estimate, saying approximately 80 bodies have been recovered so far in Jos.

The group, which became active in 2003, condemns anyone not following Muslim ideology, including strict adherence to sharia (Islamic) law. It defines itself as "followers of Mohammed and champions of Islam and holy wars."

This past July, one of the group's leaders acknowledged its solidarity with al Qaeda and threatened to attack the United States and anyone in Nigeria under "Western" influence.

In July 2009, the group killed more than 700 people over five days of attacks.