In a nation that should be enjoying its eight-month-old democracy, the scene on the outskirts of Lagos points to unsettling tensions rising with the country's newfound openness.

A van, its windshield spangled with bullet holes, guards the ruins of an insurgent ethnic organization's office, destroyed when eight truckloads of police raided the concrete-block house earlier this month. The ground is littered with scorched membership cards for the Oodua People's Congress (OPC), and the blood is up among two dozen "zonal commanders" who claim 200 men apiece under arms.

"I'm OPC!" a leader shouts.

"With all my heart!" comes the roaring reply.

This would be the "moderate wing" of a rapidly growing organization that, like others springing up in this country of 114 million, is made up of disaffected citizens who identify themselves not as Nigerians but as members of the ethnic groups that are supposed to form one nation.

"Nigeria: A People United, A Future Assured," read billboards posted around Lagos. "Welcome to the New Millennium." But other signs belie the optimism.

In the period since Nigeria elected its first civilian president after 16 years of sometimes brutal military rule, newly won freedoms are being used to express old passions. As a result, a country that needs to pull itself together shows signs of pulling itself apart.

Violent clashes between ethnic groups have erupted with regularity, so far killing more than 1,000.

In the Muslim north, three states have thrown aside federal jurisprudence in favor of the Islamic judicial system called sharia.

And across the rest of the multi-ethnic country, separateness is being institutionalized in "ethnic identity" groups. There is the Ijaw Youth Congress on the poverty-stricken, oil-rich coast; the Ibo People's Congress in the east, which already has been ravaged once by civil war; the Arewa People's Congress encompassing the north; and, between north and south, the Middle Belt Congress.

Senior Nigerian officials play down the groups' significance, even as President Olusegun Obasanjo threatens to impose a state of emergency in Lagos to suppress the most prominent of them.

"There's a freedom in the air, a freedom to take to the streets and vent," said Vice President Atiku Abubakar. And if that freedom is abused by groups such as the OPC, which actually formed to oppose the previous military government, Abubakar said the problem is best addressed in two ways: making job training available to the unemployed and shoring up a police force that is one-third the size it should be.

"I think it is more a matter of reorganizing the program to make sure there are more police on the streets," he said.

Others, however, see potent politics in the rise of ethnic identity groups, especially in concert with the sharp rise in the death toll from tribal clashes.

"In previous years there have always been clashes, but they were not as sustained or as organized," Abdul Oroh, executive director of the Civil Liberties Organization, a Nigerian human rights group, said in a report titled "Why Are Nigerians Killing Nigerians?"

Some of the groups show signs of grass-roots support rarely seen among Nigeria's political parties--which, to win a place on the ballot, must prove their appeal is not regional but national. And, in fact, the dissidents' core complaint is against the political structure, which has left some feeling oppressed.

"This democracy was sort of imposed," said Rotimi Obadofin, an officer of the Oodua Liberation Movement, yet another dissident group. "This democracy, as it is, won't solve the problem."

Of the groups, the Oodua People's Congress has garnered the most attention. Violence is one reason. Elements of the OPC have been associated with ethnic riots in Lagos that left at least 40 people dead and two police officers splashed with acid earlier this month. A third officer was carried from a police station and killed.

But the OPC is also an unlikely constituency to complain of being left in the cold. The group is named for the legendary first man of the Yoruba, the tribe that dominates Lagos and the country's populous southwest. And Obasanjo is Yoruba himself.

"Obasanjo is like the father of the nation," said OPC national secretary Kayode Ogundamisi. "But Nigeria is not a nation. It is the Yoruba nation, the Ibo nation, the Fulani nation. If Nigeria had been in Europe, you would have four nations."

Nigeria, however, is in Africa, a continent carved up by European colonialists whose boundaries the newly independent nations chose to keep in place. The British enclosed more than 250 tribes within the protectorate they dubbed Nigeria in 1914.

It hasn't been easy for the country to stay together. Tribes that clashed before independence continued to clash, but nationhood also provided something new to fight over. In the 1960s, Nigeria endured a civil war that left 1 million dead when the Igbo tried to secede and establish an independent state dubbed Biafra. The war's aftermath ushered in an era of military governments that plundered Nigeria's mineral riches--it is the world's sixth-largest producer of crude oil--and stifled dissent.

"People who have been oppressed, they now have the chance to talk," said David Babajida, 38. "During military times, if you talk, the military just comes to your house and kills you."

Now that civilians are in power again, the question is whether Nigeria can survive democracy.

"Authoritarianism provides a kind of negative stability," said Olisa Agbakoba, a leading human rights activist and lawyer. "Democracy creates space to do a lot of things, sometimes bad things, dangerous things. So democracy brings greater challenges to keep Nigeria together."

The Oodua People's Congress formed during the violent rule of Gen. Sani Abacha, the last in a line of military rulers who came from the country's north and in 1993 nullified the election of Moshood Abiola, a Yoruba. The OPC armed itself in preparation to bring down Abacha, only to see him die in 1998. The next target was whoever northerners connived to replace him with.

But, after a transitional period, Obasanjo was elected.

"Having the president alone will not solve the problem," said Abraham Adesanya, a senior Yoruba politician.

The Yoruba activists, along with counterparts in other regions, are calling for a national convention to rewrite Nigeria's constitution. They are aiming for a "loose federation" that will accommodate cries for regional autonomy, which Nigeria tried after it became independent.

Frederick Fasehun, the soft-spoken surgeon who said he founded the OPC as a "social and cultural organization," insisted the group's only political interest is in the shape of the Nigerian government.

"The unity that eluded us in the past can even come to be through these ethnic identity organizations," Fasehun said. "Why are we not using them as the building blocks of the Nigerian federation?"

Federal officials acknowledge problems and point to a panel named to review the constitution.

"There is already an awareness for amending the structure," Vice President Abubakar said. "Nobody is suggesting" that the present system is permanent, he said.

But in Lagos, the political question has become snarled in crime.

Always a relatively dangerous city, Lagos has grown even less secure since Obasanjo reined in one of the most brutal police forces. At the same time, vigilantism has risen, especially under the OPC banner. Earlier this month members burned down specific homes in a slum so tightly controlled by gangsters that the police dared not venture in.

Such outbursts have made the organization widely popular among the city's poor.

"They don't like thieves, so I like them," said Pookie Cole, 46, a beer vendor at Lagos's Yaba market.

The catch is that some OPC clearly are hoodlums. A split in the organization last year has one wing burning down houses while the original, more moderate organization pursues a political agenda. And even the moderates walk a tight line, especially regarding tensions with the northerners, known by the language they speak, Hausa.

"There is no hate. We don't hate them at all," insisted Ayo Dele Oresanya, 57, a plumber serving as an OPC zonal commander. "But they are just pushing us, pushing us. Hausa people want us to fight, and we don't want to fight."

Still, the OPC's popularity clearly underscores the inadequacy of a police force that in Nigeria is exclusively federal. Nationwide, there is one officer for 10,000 residents.

"Why can't the police do their job?" said Agbakoba, the lawyer. "It's because we have this silly idea in Nigeria that the only way to provide police is through the federal government."

After the body of an officer was dumped recently into Lagos Lagoon, the Lagos state governor lamented the onset of "anarchy," underscoring the point with an account of the three attacks he has survived since taking office .

"As a democrat, I still believe in dialogue," Gov. Bola Tinubu said, "but enough is enough."

Obasanjo agreed. The next day he sent Tinubu a letter threatening to declare a state of emergency in Lagos. In the next week, more than 500 young Yoruba men were arrested during the search for the policeman's killers.