By News Online's Justin Pearce

Fighting between Christians and Muslims in the northern Nigerian state of Kaduna is the latest challenge faced by the still-young democratic government in holding together one of Africa's most diverse countries.

Over the past year, fighting has set Yoruba against Hausa, Christian against Muslim, and communities against their neighbours throughout Africa's most populous country.

Usually, the conflict has been sparked by local rivalries, but fuelled by wider regional resentments - between the commercial hub of the south-west and the politically dominant north, or the plundered oil fields of the south-east.

Even at local level, fighting takes on an ethnic or religious character, since Christianity and the Yoruba and Ibo people are associated with the south, and Islam and the Hausa people with the north.

Nigeria's existence as a country is purely the result of borders drawn by colonial pens.

Federal flaws

At independence, a federal constitution was adopted with a view to giving a greater degree of self-determination to Nigeria's regions.

But since democracy returned to Nigeria last year, and President Obasanjo adopted a less authoritarian style of government than his military predecessors, the shortcomings of the federal system have been all too obvious.

However one might redraw the internal boundaries, there will always be states in Nigeria that reflect something of the country's ethnic and religious diversity.

The most serious ethnic clashes in recent months have occurred in cities such as Lagos and Kano which have a large ethnically mixed population.

Religious mix

And so it is with religion. As part of the greater freedoms offered under the Obasanjo government, several Muslim-dominated states in the north have expressed interest in introducing Sharia, or Islamic law.

The first state to implement Sharia was the overwhelmingly Muslim Zamfara, and there the transition passed off largely peacefully.

But in Kaduna - which has a substantial Christian minority - the mere mention of Sharia has sparked bloodshed and destruction.

Perhaps wisely, the Kaduna state authorities said they would start investigating ways in which Sharia could be introduced, rather than imposing it unilaterally.

Moreover, Nigerian Muslim leaders have said all along that Sharia will not affect the lives of the Christian minority in Sharia states.

But such assurances did little to ease the fears of Christians in Kaduna, who turned out in their thousands in an initially peaceful demonstration against the proposed introduction of Sharia.

Scuffles between demonstrators and Muslim bystanders soon grew into far more serious fighting and arson.

President's dilemma

The question now is how to contain the violence.

Police in Kaduna have appealed for reinforcements. Another more risky option would be the deployment of soldiers.

Calling out the army to quell civil unrest is bound to be politically dangerous in a country where soldiers have in the past needed little provocation in staging coups d'etat - and where the present government is trying to prove itself as the guarantor of democracy.

President Obasanjo, a born-again Christian, also has to tread carefully lest he be accused of anti-Muslim bias.

The last time the president called out the troops was in November, when soldiers went into the Niger Delta following the killing of a dozen policemen by local militant youths.

The result was yet more bloodshed, with soldiers blamed for hundreds of deaths, and President Obasanjo being forced to apologise.

Memories of that incident are certain to haunt the president as he ponders how to deal with this latest symptom of his country's difficult transition.