Nigeria's principal Islamic leader, the Sultan of Sokoto, warned that the bloody clashes between Muslim and Christian elements in the city of Kaduna posed a "dangerous and very serious threat to the peace and unity of this great nation".

In a televised address to the nation, President Olusegun Obasanjo said that ethnic and religious violence - which has claimed more than 1,000 lives since democracy was restored in May - threatens Nigeria's revival after years of military rule which plundered the nation's wealth.

"To be engaged in activities that so unsettle public peace is not only criminal but highly unpatriotic, particularly now that the international community is beginning to regain its confidence in our nation," he said.

But General Obasanjo's critics, who include some of the parliamentary leaders of his own People's Democratic party, say he is also to blame for the crisis. They accuse him of running an "imperial presidency", and say he remains aloof from ethnic and religious tensions while concentrating on solving Nigeria's enormous economic problems and staving off the threat of another army coup.

In particular, they say his failure to take a stand on critical issues such as the introduction of sharia in some Muslim-dominated states has exacerbated the crisis by giving the impression that the government is uninterested in the concerns of ordinary people.

On Wednesday, the national assembly called on President Obasanjo to make a "categorical statement" on the adoption of Islamic laws which, among other things, segregates the sexes in transport and schooling.

Many Nigerians fear that if the violence intensifies, or if the country seems to be breaking up, there are military men waiting for an excuse to seize power.

In an interview before the latest bloodshed, President Obasanjo acknowledged that ethnic and religious tensions were increasing, but insisted they would die down as the government turned the economy around: "A lot of this violence happens because when you push people to that crescendo over an issue you have trouble pulling them back. But what leads to division and conflict is inequality. We have to tackle that first," he said.

"We have stabilised the currency. We have raised foreign exchange reserves. Inflation has gone from 14% to 8%. We know there is a lot of poverty. There are problems with education and water supply. But things are moving."

Even Gen Obasanjo's critics acknowledge that in the past nine months he has achieved some notable successes. He took advantage of the near total disgrace of the army, and his own position as a former general and military ruler, to dismiss almost an entire layer of corrupt senior officers with barely a murmur of protest.

Gen Obasanjo's anti-corruption programme has also been praised for sending the right message, even if it has a long way to go before significantly curbing graft. But the president is virtually at war with parliament, which has passed just one bill in nine months, and accuses its members of wanting to be bribed to do their work, particularly after they were granted huge "furniture allowances".

"The national assembly has a problem," the president said. "The average age of the members is probably 29 or 30. They have power without knowl edge or experience, which is dangerous. They seem to get carried away by emotion or personal interest."

The president's advisers say he is so sick of the national assembly that he will use his powers to bypass it if it fails to cooperate. Some parliamentarians, who say he has already carried out his threat, have threatened to impeach him for allegedly "riding roughshod" over every other arm of government and the courts after his administration ignored an order to release from prison a former senior army officer arrested for corruption.

There is also considerable bitterness among representatives from the Niger Delta over the heavy-handed use of the army to deal with unrest in the oil-rich region, particularly in the village of Odi where soldiers massacred several hundred people and destroyed every house in November.

Gen Obasanjo denies that he is out of touch: "All the things I have done for the last eight months have been nothing but populist. The returning of looted goods, the ending of the queues at petrol stations, the going into human rights issues of the past are all popular."