Following are the main attacks linked to the Boko Haram extremist Islamist sect in Nigeria since 2009.
Rights group Human Rights Watch (HRW) says 3,600 people have lost their lives in the Boko Haram conflict since 2009, including killings by the security forces.
- July 26: Boko Haram launches a short-lived uprising in parts of the north that is brutally crushed by the military in an assault that leaves more than 800 people dead, mostly sect members.
- December 24 and 27: A series of attacks claimed by Boko Haram and reprisals in the northeastern city of Maiduguri, the sect's home base, and the central city of Jos kill at least 86 people.
- June 16: Boko Haram says it is behind a suicide blast against police headquarters in Abuja.
- August 26: Boko Haram claims responsibility for a suicide bombing against the UN compound in Abuja, killing at least 25 people.
- November 4: A series of attacks on police targets and churches in the northeastern city of Damaturu claimed by the sect kills at least 150 people.
- December 22-23: Attacks in the cities of Damaturu, Potiskum and Maiduguri claimed by the group along with a heavy military crackdown leave up to 100 people dead.
- December 25: A wave of attacks claimed by the group targeting churches during Christmas services and police leave at least 49 people dead.
- December 31: President Goodluck Jonathan declares a state of emergency in areas hard hit by Boko Haram violence - parts of the states of Borno, as well as Yobe, Niger and Plateau.
- January 20: At least 185 people are killed in the northern city of Kano following coordinated bombings and gun battles, claimed by Boko Haram.
- February 15: Boko Haram claims a raid on a prison in central Nigeria in which 119 inmates are set free.
- April 8: An Easter bomb attack on a church in the northern city of Kaduna claims at least 41 lives.
- June 17: Boko Haram claims suicide attacks at three churches at Kaduna and Zaria, sparking reprisal violence by Christian mobs who burn mosques and target their Muslim neighbours. More than 100 are killed over a week.
- October 11: Nigerian security forces as well as Boko Haram may both be guilty of crimes against humanity, HRW says.
- February 19: A French family of seven is kidnapped in Cameroon and taken to Nigeria. Boko Haram claims responsibility. The family is freed on April 20.
- March 18: A suicide attack at a bus station in second largest city Kano kills 41.
- April 19: Fierce fighting between troops and suspected Islamists in the remote northeastern town of Baga kills 187 people.
- May 7: Boko Haram launches coordinated attacks in the northeastern town of Bama, killing 55 people and springing 105 inmates.
- May 13: Boko Haram claims the Baga and Bama attacks in a video, which also depicts women and children apparently being held hostage.
- May 14: President Jonathan imposes a state of emergency in three states -- Borno, Yobe and Adamawa -- menaced by Boko Haram, saying the level of violence calls for "extraordinary measures".