Police by the thousands patrolled this central Chinese town Monday and residents hunkered down in their homes after deadly street fights between members of the country's main ethnic group and a Muslim minority.

On Monday, minivans with loudspeakers strapped to their roofs drove through the dirt roads of Langchenggang and neighboring villages in Henan province, broadcasting appeals for calm.

As many as 5,000 people fought with sticks and burned several houses over the weekend in violence between Hui Muslims (search) and members of the Han ethnic majority, according to Langchenggang residents interviewed by phone.

The fighting killed seven people and injured 42, according to residents and the government. Langchenggang residents could not confirm a report by The New York Times of 148 deaths, including 18 police officers.

Authorities imposed martial law on the area in Zhongmou County near the city of Zhengzhou (search), residents said.

Eighteen people were arrested, the government said late Monday in its first official word on the fighting. The statement, carried by the Xinhua News Agency, didn't mention the ethnicities of the rioters.

The government said the violence began after members of two families from separate villages fought over a traffic dispute.

"Afterward, residents of both villages assembled with weapons," the Xinhua report said. "One villager was beaten to death on the spot and two died in the hospital one day later."

It didn't say how the other deaths occurred.

A spokesman for the county government, Liang Songzhou, said the traffic dispute involved a collision between two farm vehicles, one driven by a Han and the other by a Hui.

Today's Hui are descended from ethnic Chinese who converted to Islam generations ago. Han Chinese make up more than 90 percent of China's 1.3 billion people. China has 55 officially recognized ethnic groups.

China suffers occasional ethnic tensions, though the level of violence isn't clear because the communist government, eager to maintain the narrative of unity it has long trumpeted, routinely suppresses reports of social conflict.

Tensions are worse in China's poor countryside, home to some 800 million people. Economic competition, disputes over scarce farmland and control of lucrative government posts often combine to cause unrest.

In December 2000, at least five Hui were shot and killed by police during protests in the eastern province of Shandong after a dispute over a Han butcher advertising "Muslim pork." Muslim dietary laws forbid the eating of pork.

On Monday, police officers lined the roads into Langchenggang beginning six miles from town. They stopped cars at checkpoints and turned some away. At least four foreign reporters who visited the area were detained.

Residents sat outside shabby brick homes beside piles of drying corn and watched silently as trucks and tour buses full of police officers roared through the main road that runs through the villages.

After dark, the roads were illuminated only by the red-and-blue lights from police sirens.

There was no visible unrest, though shattered glass was strewn across the road in Weitan, a village adjacent to Langchenggang. Villagers said the debris was left over from an altercation between soldiers and a group of men, but it wasn't clear whether the men were Hui or Han.

In its report, The New York Times said the violence erupted after a Han girl was struck and killed by a Hui taxi driver.

Another account, by an accountant in the town who would give only his surname, Liu, said the fighting began after three Hui men in a car beat up a 17-year-old Han boy who blocked the street. Liu said that confrontation escalated until a group of 400 to 500 Hui came from a nearby town and large-scale clashes took place.

"A lot of people were carrying clubs to fight. They set fire to several houses," said another Langchenggang resident surnamed Liu, who was not related to the accountant. "Right now, there are lots of police. The local government is allowing residents to move around, but everyone is afraid of going out."

Henan is one of the country's poorest regions. Langchenggang is surrounded by farmland rich with corn, wheat and cabbages.

The town was still tense Monday, according to a resident contacted by phone who said he lived a half mile from the scene of the fighting. At the height of the violence Friday, he said, he saw some 5,000 people fighting.

"I still dare not leave the house," said the man, who would give only his surname, Li. "To the west and east are Hui villages. So people are afraid to go outside."