|Inter-religious clashes have resulted in thousands of deaths throughout Nigeria [AFP]
Nigeria's population of more than 149 million people is made up of over 250 ethnic groups.
It is also split along religious lines with Muslims making up about 50 per cent of the population, Christians 40 per cent and the remaining 10 per cent registered as professing indigenous beliefs.
Religious and ethnic tensions have frequently been strained.
2000: Thousands of people are killed in northern Nigeria as non-Muslims opposed to the introduction of Sharia, or Islamic law, fight Muslims who demand its implementation in the northern state of Kaduna.
September 2001: Christian-Muslim violence flares after Muslim prayers in the city of Jos, with churches and mosques set on fire. At least 1,000 people are killed, according to a September 2002 report by a panel set up by the regional government.
November 2002: Nigeria abandons the Miss World contest in Abuja, the capital, following the death of at least 216 people due to riots that broke out in Kaduna after a newspaper article suggested the Prophet Mohammad would probably have married one of the Miss World beauty queens if he were alive today.
May 4, 2004: Hundreds of people, mostly Muslim Fulanis, the world’s largest nomadic group based in West Africa, are killed by Christian Tarok fighters in the central Nigerian town of Yelwa. Survivors say they buried 630 corpses .
May 12, 2004: Muslim and Christian fighters wage street battles in the northern city of Kano. Christian community leaders say 500-600 people, mostly Christians, were killed in two days of violence.
February 2006: At least 157 people die in a week of rioting by Muslim and Christian mobs. The violence begins in the northeastern city of Maiduguri when a Muslim protest against Danish cartoons of the Prophet Mohammad runs out of control. Revenge attacks follow in the south.
November 2008: Clashes between Muslim and Christian gangs triggered by a disputed local government election kill at least 700 people in Jos, according to the US-based Human Rights Watch.
February 22, 2009: The governor of Bauchi state imposes a night curfew on Bauchi city, a day after clashes in which at least 11 people were killed, 28 are seriously wounded and several houses, churches and mosques set on fire.
July 26, 2009: Boko Haram, an organisation that opposes Western education and demands the adoption of Sharia across Nigeria, stages attacks in the northeastern city of Bauchi after the arrest of some of its members. More than 50 people are killed and over 100 arrested.
July 27, 2009: Police in Maiduguri, home of Boko Haram's leader Mohammed Yusuf, say security forces killed 90 sect members on July 27. In neighbouring Yobe state, police recover the bodies of 33 sect members after a gun battle near the town of Potiskum on July 29.
July 30, 2009: Boko Haram leader Yusuf is shot dead while in police detention in Maiduguri. Meanwhile, Red Cross and defence officials say more than 700 people were killed during the five-day Boko Haram uprising.
December 2009: At least 40 people are killed in clashes between security forces and members of an Islamic sect armed with machetes in the northern city of Bauchi.
January 2010: Hundreds of people are reported killed after clashes between Muslim and Christian gangs in Jos. Violence abates after the military is sent to the area and a curfew is imposed.
March 7, 2010: Hundreds of people are reported killed after clashes between pastoralists from the surrounding hills and villagers close to the central city of Jos. Arrests follow and security forces vow to hold the state's security officials to account for future outbreaks of violence.
March 17, 2010: At least 13 people killed in attack by Muslim herdsmen on village of Byei, just 30km south of Jos.
July 17, 2010: A church is burned and eight people hacked to death in an attack by Muslims in Mazzah village, located 14km from Jos.
October 1, 2010: The Movement for the Emancipation of the Niger Delta, the dominant militant group in the region, claim responsibility for dual car bombings during Nigeria's 50th independence anniversary celebrations in the capital that killed at least 12.
December 24, 2010: A series of bombs go off in villages near Jos, the main city, in Plateau state, killing 32 people and leaving 74 others in critical condition.
December 31, 2010: A bomb explodes in an open-air beer garden and market at an army barracks in Abuja, killing at least four and wounding at least 21.
January 2011: Fresh sectarian violence between Christians and Muslims flare up in central Nigeria, killing at least 35. Various places of worship are targeted, while religious rioting and arson attacks continue on the streets in the city of Jos and Tafawa Balewa.
May 30, 2011: A series of blasts hit cities mainly in northern Nigeria, killing at least 12 people. The attacks came less than 24 hours after the inauguration of Goodluck Jonathan as president.
June 8, 2011: Boko Haram orchestrates multiple blasts and targeted attacks by on two police stations and a church in the country's restive northeast. Up to 11 people are killed.
June 16, 2011: Boko Haram claims responsibility for a suicide bombing in the car park of the police headquarters in capital Abuja. At least two people are killed, including the bomber. The attack is reported to have been Nigeria's first suicide bombing attack.