Following the implementation of shari'a (Islamic law) in Zamfara state on October 27, four other states in northern Nigeria Bauchi, Katsina, Borno, and Yobe are preparing to adopt shari'a as their legal system. Thousands of Christians in Kaduna, led by the Christian Association of Nigeria, took to the streets in protest.

Observers say the states' decision is pushing Nigeria to the brink of a religious war. The crisis began over two decades ago, when Nigeria's Muslim political leaders moved to align the country with other Islamic nations, although half the population is Christian. Muslims predominate in the north, with some estimates running as high as 90 percent of the region's population. But with a secular constitution, the states' move toward shari'a which regulates Muslim life and prescribes punishments such as stoning and beheading has divided the country even further.

Many Muslim religious leaders are unbending. "It is on the basis of freedom of worship that people in these states, who are predominantly Muslims, want to be governed by the laws of their religion," says Sheikh Abubakar Jibrin, the imam (Islamic cleric) of Fasfam Mosque in the northeastern city of Sokoto.

"Muslims in Nigeria are tired of unnecessary criticisms and outright attacks on us and our religion by those who should know better," says Sheikh Ahmed Sanusi Gunbi, another Islamic leader. "We are therefore prepared to shed blood to defend our religion."

Alhaji Balarabe Musa, a former governor of Kaduna state in northern Nigeria, insists shari'a is superior to the Nigerian constitution.

But Sunday Mbang, president of the Christian Association of Nigeria, says shari'a violates the constitution, and Catholic bishops ...