Boko Haram, a radical Islamist sect, said on Tuesday it was behind bombings in central Nigeria and attacks on churches in the northeast of the country that led to the deaths of at least 86 people.
Here are some facts about the group:
* It became active in around 2003 and is primarily concentrated in the northern states of Yobe, Kano, Bauchi, Borno and Kaduno.
* In July 2009, Boko Haram staged attacks in the northeastern city of Bauchi after the arrest of some of its members. Clashes also took place in the northern city of Maiduguri. More than 700 people were killed during the five-day uprising by the radical Islamic sect.
* In the same month, sect leader Mohammed Yusuf was shot dead in police detention, hours after being captured by Nigerian security forces.
* In early July 2010, Abubakar Shekau, a former deputy leader of the sect who was thought to have been killed by police in 2009, appeared in a video and claimed leadership of the group. He said he was ready to launch attacks on western influences in Nigeria.
-- On July 13, Shekau issued another statement expressing solidarity with al Qaeda and threatened the United States.
* Boko Haram -- which in the Hausa language spoken across northern Nigeria means "Western education is sinful" -- is loosely modeled on the Taliban movement in Afghanistan.
* The group considers anyone not following their strict ideology, whether Christian or Muslim, as infidels. The group demands the adoption of Islamic sharia law in all of Nigeria.
* Boko Haram followers have prayed in separate mosques in cities including Maiduguri, Kano and Sokoto, and wear long beards and red or black headscarves.
Sources: Reuters/Janes World Insurgency and Terrorism, 2010
(Reporting by David Cutler, London Editorial Reference Unit; editing by Mark Trevelyan)