TIKRIT, Iraq -- "Tikrit is like the Mason-Dixon line," said a sergeant in the U.S. Special Forces operating in Saddam Hussein's hometown. "The further west you go the more Arab it is, the further east you go the more Kurdish it is."

Lying on an arid sandy plain in northern Iraq, with squat mud houses and a hostile population, Tikrit seems more like the Wild West than pre-Civil War America. The sergeant's analogy works, though, because the disgruntled citizens of Tikrit may be the ones who provoke a civil war in Iraq -- attacking U.S. forces and the Kurds, Shiites or other Iraqis who support them.

So far, Tikritis are mounting only a small guerrilla war. But if per capita waves and smiles were a standard by which to judge a town's reaction to U.S. troops, the sentiment in Tikrit is clear.

In other parts of the country, children, adults, even old men, wave and smile at U.S. soldiers from their perches on street corners and cars. In Tikrit they glare.

While anti-American graffiti is commonplace on the walls of every Iraqi city, only in Tikrit and neighboring villages is there pro-Saddam graffiti that calls for a holy war against the Americans.

Every morning, formerly empty walls are painted with "Long live Saddam!" and words calling for his return to power. Tikrit still has a Saddam street, a Saddam hospital, a Saddam mosque. One student at the university joked that Tikrit used to have "Saddam air and Saddam water also."

Unlike other towns and cities, Tikrit did not suffer from an orgy of looting directed at symbols of authority, perhaps because the population bore no hostility to the former government. Also, unlike other cities, Tikrit apparently does not suffer from shortages of water or power.

U.S. special forces send their helicopters through the skies and their convoys down the streets of Tikrit with greater visibility than elsewhere, as they hunt down former regime members and active guerrilla fighters.

The U.S. troops are based in dozens of elegant palaces surrounded by artificial lakes, waterfalls, islands and swimming pools. Even the chandeliers and columns bear Saddam's initials. And they have minimal interaction with the locals, as they rumble from one base to another in large convoys, now and then bursting into homes to arrest suspects.

The Mashallah restaurant is an Iraqi version of an American truck stop, always full and boisterous. It got quiet and emptied when several American soldiers entered for lunch. There were none of the warm welcomes that typify Iraqi culture.

One white soldier commented, "I feel like a black guy walking into a Country and Western bar in the South." The food was hastily brought and removed. An olive skinned companion in civilian clothes drew hateful stares since it was presumed he was an Iraqi traitor working with the Americans.

In Tikrit people are afraid to talk to U.S. soldiers in public; they steal a few words here and there in alleys. A local factory that sells ice to the Americans received so many threats that U.S. troops are now posted to protect it.

Cars slow, and passengers extend their necks to eye strangers. "Tikrit is a small town," said one taxi driver, "and we recognize anybody new." By 9 p.m. the streets empty, and Tikrit becomes a ghost town in anticipation of a 10 p.m. American-imposed curfew.

Three children have been accidentally run over by American soldiers in Tikrit, tragedies to be sure, but there are other public relations nightmares, as well. An angry old man in a black robe and traditional head scarf swears he is heading to his tribe to collect weapons and allies to attack the Americans because they had shot one of his relatives.

Assim Abdullah, a university student originally from another town to the north, said, "95 percent of Tikritis supported Saddam but they [claim to have] changed 180 degrees now that he is gone. They all benefited from him. Only five percent of Tikritis are innocent. The others supported Saddam, they helped him and they took advantage of their power to increase their wealth, so you can recognize the innocent people. If they are rich, they are not innocent."

The Saddam mosque in the center of town may be the cleanest, best lit and best air-conditioned mosque in the country. It is new, and no expense was spared. Several hundred men sat between the wide intricate columns of the mosque to hear the Friday sermon last week.

"I told you many times not to attack the Americans now," said Sheikh Kheiri, the preacher, exhorting his flock to "wait and prepare yourselves. Your enemy is very strong and whatever you do you cannot defeat him. When you organize yourself secretly, and plan secretly and collect weapons secretly, then you will succeed in whatever you do. Don't let your enemy know what you are doing. Your government is gone, your supporters are gone, everything is gone right now."

Kheiri admonished his listeners, who numbered about 500, for supporting Saddam's Baath party and for straying from Islam. "This is why the Americans are here," he said.

"Mohammed worked secretly for three years before he began his campaign for Islam." He urged them to organize and recruit people, warning against small random attacks because "you are between the lion's teeth, and if you do anything he will kill you and your family. Don't do anything until we tell you."

The speech resembled the recent sermon in Baghdad of Iraq's most prominent Sunni cleric, Sheikh Ahmad Kubaisi, when he condemned attacks against American soldiers not because they were wrong, but because they were premature.

"We waited 35 years under Saddam, and we should give Americans a year before we fight them and tell them to leave," Kubaisi said. He has referred to the Americans as the new Mongols, the barbarian hordes who sacked Baghdad in 1258.

Tikrit is nearly all Sunni Muslim. It was therefore odd to hear an American officer discussing his concerns about "Shiite fingers" extending from Iran to attack U.S. forces -- an entirely implausible scenario but a demonstration of the degree to which the Americans seemed oblivious to what was transpiring less than a mile from their base, where attacks were being urged and planned by Sunni clerics while the Americans fret over an imagined Iranian threat.

An English teacher employed by the U.S. military as a local translator attended the Friday sermon and later defended it. "He is a moderate," Abbas al Tikriti said of Kheiri. "Of course he is calling for attacks against the Americans eventually; they are occupiers."

A local taxi driver believes he has divined American intentions. "They want to wipe out Islam," he said. "Iran is next and then Syria. But Iran will be the end of America. Just as Hitler was destroyed when he tried to conquer the world, so, too, will America be destroyed."

The Americans appointed a governor for Tikrit from the Juburi tribe. This only increased local consternation.

The new governor appointed his relatives to all official positions, including as police officers and college deans. "Saddam did the same thing," an observer commented. The governor's office is guarded by dozens of relatives sporting an array of pistols and machine guns.

The nearby town of Balad elected a leadership council, but the Juburi did not recognize it. According to a U.S. soldier familiar with the situation, Juburi are now persona non grata in Balad, Baquba and Samara, three towns in his jurisdiction.

The Juburis' authority ostensibly extends to Samara, but there is a growing movement for autonomy. Local signs refer to the "governorate of Samara."

Many of the mullahs in the region around Tikrit are relatively moderate, like Sheikh Ahmad al Abasi at the Alburahman Mosque of Samara. He has advised his followers to work with the Americans, but that "if after a year they do nothing for the people here, we will tell them to go home."

Ahmad bin Hamad preaches angrier sermons. His mosque in Samara, reputed to be Wahabist, the same strict brand of Islam that dominates Saudi Arabia, is known for telling Muslims to resist the American occupation. Graffiti on the mosque walls support Ansar al Islam, the radical group associated with al Qaida that U.S. and Kurdish troops fought in the north. Until recently there was also a weapons market nearby.

American officials are now debating whether to arrest religious preachers who incite violence, even if only in the future. One Army officer, who feared revealing his name, was harshly critical of such a policy.

"It will only make them martyrs," he said. "It treats the symptom and not the cause."

The cause, the occupation itself and the sudden disenfranchisement of the Sunni minority that controlled the country under Saddam, does not yet have a cure.