The Islamist insurgency in Nigeria, also known as the Sharia conflict in Nigeria, began in 1999 with the establishment of sharia law in several Muslim-majority states in Northern Nigeria, despite the secular Constitution of Nigeria and the disagreeing Christian minority. From 2000 onwards, occasional riots between Christians and Muslims have resulted in thousands of deaths. Since 2009, when the Islamist group Boko Haram started an armed rebellion against the secular government of Nigeria, the conflict has become more violent. In 2010, 55 people were killed in claimed or suspected Boko Haram attacks. By 2013, the annual death toll exceeded 1000, with a further sharp increase occurring in early 2014.
According to a Nigerian study on demographics and religion, Muslims make up 50.5% of the population. Muslims mainly live in the north of the country; the majority of the Nigerian Muslims are Sunnis. Christians are the second-largest religious group and make up 48.2% of the population. They predominate in the central and southern part of the country.
As Muslims narrowly form the majority of the population, many of them demand the introduction of Sharia – the Islamic law – as the main source of legislation. Twelve Northern states have introduced sharia as a basis of the executive and judicial branches of government in the years 1999 and 2000.