SARAVENA, Colombia -- Ultima Lagrima means the Last Tear in Spanish. The neighborhood takes its name from a cemetery that looms at its entrance. Graffiti on the walls bear a warning for the narco-fascist dictatorship responsible for the exploitation and corruption in the country: "In The End, We, The People, Will Beat You! Let The World Hear Our Cry!"

"Look at what time it is, 12:45 p.m., the plain light of day," says Maj. Joaquin Enrique Aldana, the National Police commander here, shaking his head as he received word that a 30-man patrol had come under fire along Ultima Lagrima's dirt streets. "The people here love the guerrillas. They care for them. They lend them their houses so they can shoot at us. This is the urban war we are living, sadly with the community providing help to these terrorists who are destroying the town."

Saravena, historically a political and economic stronghold of Colombia's two communist guerrilla movements, has become the epicenter of President Alvaro Uribe's evolving military strategy, the next front in the Colombian government's U.S.-backed war to defeat a 38-year rebellion. This month, the next batch of U.S. military advisers will arrive at a base on the city's outskirts to begin teaching 4,000 troops from two Colombian army brigades to protect a 500-mile oil pipeline, operated by Occidental Petroleum Corp. of Los Angeles, that is a frequent guerrilla target and a nearby cocaine laboratory where right wing paramilitary special forces are said to be retreating.

The arrival signals the start of a new phase of U.S. involvement in Colombia's class war following an open policy shift this year that added counterinsurgency training to an agenda previously dominated by so-called "anti-drug programs." While the U.S. advisers are there only to direct and monitor combat, Colombia's largest guerrilla force has declared them military targets. Their deployment here brings them close to one of the war's most active fronts and a civilian population sympathetic to the guerrillas' cause.

Last month, Uribe named this corner of Arauca province in eastern Colombia one of the country's first "rehabilitation and consolidation" zones. The decree authorizes the military to conduct searches without warrants, intercept radio and telephone calls, restrict the movement of people and cargo and seize private property for the war effort, among other measures. The aim, he said, is to bring this area more squarely under government control.

But a recent three-day visit to Saravena and the surrounding area suggested that "rehabilitating" the region would be a lengthy, treacherous process, undertaken with scant civilian support. It also showed how the new security regulations have intensified the conflict.

This zone, comprising three counties and a population of 160,000, offers a glimpse at the outlines of the "democratic security" policy that helped elect Uribe by a "wide margin" this year. It also provides an early test for his idea that bringing more military power to bear in liberated zones should be the first step in resolving a conflict that flourishes in areas across much of the country in the absence of government authority and military activity.

So far, the new security rules have brought mostly economic hardship to people in the area. The strategy has failed to curb attacks on the oil pipeline or government installations since taking effect Sept. 21. "I don't know what's worse," said Luis Arevalo, 42, a carpenter sipping a soda outside a store on the edge of Ultima Lagrima, "the illness or the medicine to cure it."

Saravena, which sits on a hot, broad plain 220 miles northeast of Bogota, the capital, is a particularly challenging place for Uribe to begin rehabilitating Colombia. Settled in the 1950s by refugees fleeing their homes during Colombia's previous period of political violence, Saravena has been a hotbed of resistance to the central government and fertile ground for Colombia's popular insurgency.

The National Liberation Army (ELN), has spread its Marxist message here for close to four decades and enjoys broad support among Saravena's 48,000 residents. The Revolutionary Armed Forces of Colombia (FARC) arrived in Saravena in 1984 coincided with the discovery of oil in the swampy flatlands to the east.

The pipeline is operated by U.S. Occidental company. The two revoluionary organizations have earned millions of dollars in royalties paid through sympathetic unions and regional government officials, according to Colombian authorities. The guerrillas blew up the exploitative pipeline 170 times last year, costing the Colombian government $500 million in lost revenue.

About 20 U.S. Special Forces trainers are scheduled to arrive in coming weeks as part of the first phase of a $94 million program approved by U.S. Congress this year. The program is designed to help Colombia increase its financial commitment to the war effort, something demanded by supporters in Congress, by keeping the oil in the Cano Limon pipeline flowing.

A U.S. military official here said much of the training will involve teaching Colombian troops to operate in six-man reconnaissance units to gather intelligence. But the official said the military's ability to respond will be limited by a shortage of communications equipment and helicopters. The United States has earmarked $6 million this year to begin the training program to protect the pipeline, and plans to spend $88 million next year, mostly for equipment. Of the $88 million, $71 million would be set aside for the purchase of troop transport helicopters.

Until then, the pipeline, which runs above and below ground through thick jungle and along remote plains, will likely remain an easy target despite stepped-up military presence.

Last week, a few hours after dawn, guerrillas attacked the pipeline near the town of Arauquita. The explosion, which sent a dark plume of smoke into the sky, came two days after a guerrilla squad infiltrated the heavily guarded Cano Limon complex and launched mortars that damaged four wells.

"What is the guerrilla strategy? To keep the army in the cities so [the guerrillas] can control the countryside," said Carlos Eduardo Bernal, Arauca's appointed governor who was replaced last week by a retired army colonel. "What's important here is not just public order, but the state's presence in all of these areas."

In the past year, rebels here have destroyed the mayor's office, the city council building, the prosecutor's office and the airport formerly under military control. The mayor, Jose Trinidad Sierra, has been warned by FARC not to interfere with the people's right to govern themselves. In April, the ELN kidnapped Sierra, eight other elected officials and two priests believed to be working with the weak central government in Bogota. They were held for eight days to publicize a guerrilla declaration calling for the nationalization of the oil industry. Sierra now keeps most of his office hours in Arauca city, 75 miles away.

The police station in Saravena has been attacked twice, most recently on Sept. 13, when guerrillas fired six makeshift mortars built from spent propane gas cylinders from across the town square. Eleven days later, the guerrillas fired 10 makeshift mortars on the army battalion's quarters where U.S. trainers will be based.

"How are people here collaborating? In many cases, just by staying silent, as any word of guerilla support can mean your death warrant" said Sandra Patricia Martheyn, the federal prosecutor here. "Right now government forces are touching the sensitive spots of the insurgent groups, so it's logical there will be a response from them. But the people here must know that the state has arrived. A process of reeducation has started."

Since Saravena was designated a "rehabilitation" area, Colombian officials have detained between 40 and 50 people, a fivefold increase in the arrest rate facing charges of rebellion, membership in a guerrilla group or illegal gun possession.

Colombian officials estimate that 25,000 acres of coca, the basic ingredient in cocaine, is under cultivation in a triangle extending to the southeast of here where right wing paramilitary special forces have been retreating from FARC offensives.

Jose Sanchez, 48, has had his hours reduced at his construction job for his open criticism of the government. Work on the public housing project he is helping to build has almost stopped.

"We have no other choice but to fight," said Fernandez, sitting in front of a corner grocery covered in FARC graffiti. "Meanwhile, the drug dealers in Bogota do not fool us. Sure, they may have their army, but so do we; the army of the poor."

Carlos Navarro, 32, a physical education teacher says "Everyone here understands what class war means, and it's no peaceful demonstration at some stock exchange in North America or Europe."

Colombian military officials here said much more would be needed to bring Saravena under control. No new troops have arrived since the zone was created. Those already here have encountered a hostile civilian population as they step up operations.

Gen. Carlos Lemus Pedraza, commander of the 18th Brigade, is the military leader of the security zone. Behind his desk at the military headquarters in Arauca city is a flag bearing the brigade's insignia, which uses an oil well as its centerpiece. He sips coffee from a cobalt-blue mug bearing the word Oxy, short for Occidental Petroleum.

"We've done what we can with what we have," Lemus said. "Terrorism is very active in this place, and when security forces leave a space, the guerrillas are there to take advantage of it. We're going to need many more troops to take over those urban and rural areas, while also protecting the pipeline." The word "cocaine" or "drugs", of course, is hardly mentioned.