Guerrillas Step Up Campaign in Paraguay TACUATÍ, Paraguay - The guerrillas appeared at dusk. Wielding assault rifles, they arrived at the remote cattle ranch clad in "para'i," or camouflage, according to survivor accounts in Guaraní, the indigenous language that prevails here in Paraguay's northern frontier. They abducted security guards at the Brazilian-owned ranch, freed a supervisor, who then rushed to inform the authorities, and ambushed the police officers who arrived at the scene. By the time the well-orchestrated raid in August had ended, five people were shot dead, including a police officer. The attack was the deadliest yet by the Paraguayan People's Army, or E.P.P., a shadowy Marxist rebel group exerting influence across vast stretches of this California-size nation of 6.6 million people. "This is already a declared war against the republic," said Francisco de Vargas, the interior minister. Insurgencies by groups like the Paraguayan People's Army, which has been meticulously picking off security forces in remote frontier settlements, planting bombs under police vehicles, and kidnapping and killing wealthy Paraguayans, find a lot less maneuvering room in Latin America these days. Around the region, many such groups have been hunted down or incorporated into leftist political parties as military dictatorships gave way to democracies and dissent began emerging in different forms. Even where guerrillas persist, they are significantly winnowed down, like the Shining Path in Peru, or pursuing peace talks with the government, like the Revolutionary Armed Forces of Colombia. Then there is Paraguay, one of Latin America's poorest and most unequal nations. Even as the economy booms, the Paraguayan People's Army is evolving from a ghostlike irritant for the authorities in Asunción, the capital, into a broader security threat in a backcountry that is already a hub for traffickers of marijuana, defiantly cultivated here on sprawling plantations, and Andean cocaine smuggled into Brazil and Argentina. Nearly everything about the Paraguayan People's Army is in dispute, from its size to its ideology, with an important exception: The group's operations are intensifying this year, building on a slow-burning insurgency in areas where the guerrillas are thought to draw support from impoverished farmers chafing at the expansion of large-scale soybean farms and cattle ranches. The group is carrying out attack after attack on isolated police and army posts, while pursuing targeted killings of peasants accused of collaborating with security services. Bivouacking in the dense remnants of the Atlantic Forest that once blanketed much of Paraguay, it has eluded every military campaign aimed at eradicating it. While the official estimates of victims killed by the group remains relatively low, numbering in the low dozens, pockets of northern Paraguay have nevertheless taken on the semblance of a war zone as the central government ramps up military patrols and deploys special operations units to find the guerrillas. In Tacuatí, a town of 11,000 people that is thought to be a Paraguayan People's Army bastion, police officers barely out of their teens nervously grasp rifles, squinting at visitors behind a makeshift barrier of sandbags. Tanks roll down nearby country roads. Personnel trucks carry elite army forces, their faces covered in bandannas. "The soldiers think they'll find the E.P.P.," said Elizabete Schneider, 32, the owner of a small food store on the lonely road into the town. "But the guerrillas are like phantoms," she said. No one sees them; no one talks about them. Army units chasing a mysterious rebel group credited with a baffling elusiveness: it sounds retro enough to evoke old tales like Graham Greene's 1973 novel, "The Honorary Consul," about hapless guerrillas from, of all places, Paraguay, led by a renegade priest who kidnap the wrong man, a whiskey-soaked Briton. The Paraguayan People's Army is believed to have been created by trainee priests, similar to the rebels in Mr. Greene's book, in 1992 who abandoned a seminary. The group originally functioned as a cell of a leftist political party and was implicated in the 2004 abduction of Cecilia Cubas, the 32-year-old daughter of Raúl Cubas, Paraguay's former president. Her corpse was found in a shallow grave near Asunción in 2005 after her family had paid a ransom for her release. "The E.P.P. are Marxists who want to take over Paraguay," said Bernardo Cristaldo Mieres, 35, a Roman Catholic priest in the town of Choré whose younger brother, Manuel Cristaldo Mieres, a leader of the group, is thought to have masterminded Ms. Cubas's kidnapping. The priest said he had not spoken with his brother for nine years. "I don't support his violence," he said. Estimates of the Paraguayan People's Army's size now range from a little more than a dozen hardened combatants to as many as 150, in addition to a broader support network in poor villages. The group's most prominent published document, a manifesto by Alcides Oviedo Brítez, an imprisoned leader, is "surprisingly shallow and unimpressive," said Andrew Nickson, an expert on Paraguay at the University of Birmingham in Britain. In the manifesto, the group, which adopted its current name in 2008, proposes the destruction of "imperial-bourgeois democracy" and lauds José Gaspar Rodríguez de Francia, the despot who tried to seal off Paraguay from the outside world in the 19th century, establishing a bizarre police state while declaring himself head of the landlocked nation's Roman Catholic Church.