President Olesegun Obasanjo has made an impassioned plea for calm in the northern Nigerian city of Kaduna, where more than 300 people are reported to have been killed in recent fighting between Christians and Muslims.

The fighting erupted after Christians protested against the proposed introduction of Islamic Sharia law in the state.

Our West Africa correspondent Mark Doyle witnessed the corpses of Muslims lying abandoned in Christian neighbourhoods, while in predominantly Muslim areas, dead Christians are left to rot.

He says each community apparently set out not only to kill but to destroy the livelihood of the other.

In a televised speech to the nation, President Olesegun Obasanjo said the horrors of Kaduna had achieved nothing.

"What we need most now is love, caring for each other and joining of hands to rebuild the nation together," President Obasanjo said.

"Let us bind our wounds and accept the challenge of the time."

But not wanting to alienate either religious group, he made few specific proposals about how to prevent further fighting.

Army reinforcements have flooded into Kaduna, and have put an end to the worst of the fighting.

Officials at the main hospital say more than 300 bodies have been brought in. A correspondent for Reuter news agency said the mortuary of the Ahmad Bello University teaching hospital was filled to capacity and extra bodies were laid on the floor, many of them charred by fire.

But thousands of people are sheltering in army barracks and police stations in fear of their lives after three days of violence.

Hundreds of homes were burnt in the fighting.

With life slowly returning to normal, state authorities have eased the curfew to between 1600 and 0700 and set up a panel to investigate the reasons for the fighting.

Court case

Nigeria's Human Rights Law Service has meanwhile begun court proceedings to try to have Sharia declared unconstitutional in Zamfara - the first state to adopt the Islamic legal code.

Despite the clashes in Kaduna, other predominantly-Muslim states in northern Nigeria have taken steps to introduce Sharia law.

The governors of Niger and Sokoto States have both signed bills under which Sharia is expected to come into effect in May.

Two others states - Kano and Yobe - are considering similar moves.

The Sharia issue has become increasingly divisive in Nigeria since Zamfara State announced it would introduce the code last October.

Muslims are pressing for its wider introduction, and have repeatedly stressed that Sharia will not affect Christians.