|Analysts say the violence is linked to poverty more than religion [AFP]
The group behind a number of high-profile violence in Nigeria is known by several different names, including al-Sunnah wal Jamma, or Followers of Muhammad's Teachings, and Boko Haram, which means "Western education is forbidden".
The group considers anyone not following their strict ideology, whether Christian or Muslim, as infidels, and demands the adoption of sharia law in all of Nigeria.
It was founded in 2002 in Maiduguri, the capital of Borno state, allegedly by Mohammed Yusuf, a religious teacher.
In 2004, it moved to Kanamma in Yobe state, close to the border with Niger, where it set up a base dubbed "Afghanistan," from which it attacked nearby police outposts.
In July 2009, Boko Haram staged attacks in the northeastern city of Bauchi after the arrest of some of its members.
Bauchi is one of 12 states in northern Nigeria where sharia, or Islamic law, is practised.
Sectarian clashes between Muslims and Christians in Bauchi state in February left at least five people dead.
Muslims attacked Christians and set fire to churches in retaliation for the burning of two mosques, which had been blamed on Christians.
In November 2009, more than 700 were killed in Jos, capital of Plateau state, when a political feud over a local election degenerated into one of the bloodiest confrontations between Muslims and Christians.
In the same month, the group's 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 Boko Haram 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.
Analysts have also said that at the heart of the recurring tension is dire poverty and political manoeuvring - not religion.
Experts say attacks are committed mainly by frustrated, unemployed youths and orchestrated by religious leaders and politicians who manipulate them to retain power.