It does not take much to spark a riot in this downtrodden desert city long regarded as Jordan's version of a Wild West frontier town, where small-time traders, unemployed laborers and Bedouin tribesmen mingle with smugglers and firebrand Muslim preachers.

In 1989, the riot was over the cost of fuel. A few years later, it was the price of bread. And in 1998, it was the U.S. and British airstrikes on neighboring Iraq.

Each time, order was restored after officials persuaded prominent religious and tribal leaders to hand troublemakers over to the authorities. But this week, with the threat of a U.S.-led war on Iraq stoking tensions across Jordan, the government took a different tack to try to suppress unrest in Maan: It sent in tanks.

The crackdown, which has involved thousands of soldiers and police officers, underscores the fears of public revolt across the Arab world in the event of a U.S. attack on Iraq, and the extraordinary steps governments in the region are taking to ensure they stay in control.

Anticipating violent protests and acts of retribution against American interests as well as those of U.S. allies, Jordan, Egypt and Persian Gulf states have taken additional security precautions in recent months, according to officials, diplomats and analysts. The measures range from keeping more troops on standby and increasing the frequency of riot-control training to rounding up government opponents.

"There is an enormous amount of concern," said Adnan Abu Odeh, a political adviser to the late King Hussein, father of the current king, Abdullah. "We cannot handle the earthquake of another war in the Arab world."

Officials here and in Amman, the capital, have shied away from casting the security operation as a preemptive strike to prepare for a possible war with Iraq. Instead, they said the troops are pursuing "a gang of outlaws" allegedly involved in arms smuggling and drug dealing in Maan, which lies 130 miles south of Amman, at the point where a major road connecting Jordan to Saudi Arabia intersects with the main highway from Amman to the Red Sea port of Aqaba.

Taking the unusual step of calling on the military to deal with domestic instability, the government dispatched tanks and armored personnel carriers to Maan on Sunday. But instead of a quick sweep through the hilly town to pick up miscreants, security forces encountered pockets of resistance. Gunfights ensued and the troops shelled several homes, witnesses said.

Officials said five people were killed , but residents put the figure at at least 10, with scores more wounded. More than 80 people have been arrested and dozens of weapons, as well as bombmaking material, have been confiscated, the officials said.

The police today lifted a curfew imposed since Sunday, allowing people to visit the market and mill about on the streets. But signs of the security operations were everywhere as a group of foreign journalists were escorted to the city by the Information Ministry. Blue armored personnel carriers and special operations troops were stationed at almost every corner as forces continued sweeping the city.

The trouble started Oct. 27, officials said, when Mohammad Ahmad Chalabi, an outspoken Islamic preacher, shot at police officers who had stopped him for a traffic violation on the highway to Amman. Wounded in the shootout, he was taken to a hospital in Maan, where his supporters forced the police to free him by threatening to burn the hospital down. The group then disappeared in the labyrinthine neighborhood of Al Tour.

Officials said the troops were sent in on Sunday after Chalabi refused to surrender and local leaders refused to turn him over.

The governor of Maan, Mohammed Breikat, accused Chalabi of running a "professional gang" that "started to terrify the people of Maan." The governor said the gang attacked government buildings, tried to rob businesses and shot at college students.

"Because of the amount of violence committed by this gang, the people of Maan demanded protection from the government," he said.

But several residents, interviewed briefly before reporters were ordered back on a police bus, depicted Chalabi not as a gangster but as an Islamic activist with fundamentalist and anti-Western views. He reportedly organized a demonstration last year in support of Osama bin Laden, an event that led the government to revoke his permit to preach in mosques.

"He's God, God, God -- 24 hours," said one man who, like most people interviewed here, refused to provide his name because he said he feared retribution from the government. "He doesn't know drugs. He doesn't know terrorism."

Another man, standing in the door of a barber shop, called the crackdown political. "This has nothing to do with gangs," he said. "It's because of the situation in Iraq."

Many Jordanian political analysts agree. "It's hard to buy the argument that this is because of an outlaw element," said Radwan Abdullah, a political scientist. "The problems in the south have been going on for more than 14 years."

The military operation in Maan, he said, "is all about an insecure government maintaining control."

Unemployment, and a feeling of being ignored by the central government, is greater in Maan and other towns in the south than in most of the north. Tribal ties and fundamentalist Islamic leanings are stronger in the south.

"Even though the main grievances are economic, political circumstances like a war in Iraq can serve as a trigger for protest, for people to vent their frustrations," said Abdullah, the analyst. "The government cannot afford to let these sentiments get out of hand."

Analysts said the policy could backfire by cementing hostility that has been bubbling for several years. As residents inspected the bullet-pocked limestone walls of their homes and the charred remains of shelled buildings, they derided the government's strategy. Near the market, several residents shouted criticism at police officers escorting the group of journalists.

"They destroyed our homes," one man shouted.

"They had a grudge," another said.

At the barber shop, a man picking his teeth with a small stick said the government should have tried to resolve the standoff peacefully.

"They could do it other ways," he said. "You don't imprison the town."