Leading a squad from his "unconventional unit" of elite Scout Rangers and former communist guerrillas, Col. Rodolfo Aguinaldo walked into a police field company camp after six hours of tracking a rebel band through the jungle near this northern town.

"They really run fast," he said as he set down his Israeli-made Galil assault rifle and pulled off his black beret. The squad had found no trace of the estimated 40 communist New People's Army guerrillas who had ambushed eight policemen in a jeep that morning.

The guerrillas had killed one policeman, wounded four others and made off with several M16 rifles. But local forces had failed to pursue them, leaving it to Col. Aguinaldo to fly in with his squad by helicopter from another provincial camp and give chase.

One of the few colonels personally leading men on patrols, Aguinaldo is fighting both to quell a tenacious rebellion and revitalize a lax, ill-equipped and demoralized military in this embattled province of Cagayan on the main island of Luzon.

Dubbed "the Rambo of the Philippines" by fellow officers, the 38-year-old colonel was one of the original members of an armed forces reform movement that revolted against former president Ferdinand Marcos. Since the overthrow of Marcos, Aguinaldo has been promoted to Cagayan provincial commander and now oversees counterinsurgency operations in perhaps the hottest guerrilla war zone in the country.

While regional guerrilla fronts in other parts of the country have scaled down their activities or taken a wait-and-see attitude toward the new government of President Corazon Aquino, guerrillas in this northern province appear to have escalated their attacks on government forces.

Among the casualties in the last three months have been the mayor of Gonzaga, Francisco Baclig; two Filipino journalists, including Reuter photographer Wilfredo Vicoy; and more than 75 troops.

The rebel upsurge and the government's counterinsurgency campaign have made the conflict in Cagayan perhaps the closest thing in the Philippines to Vietnam-style combat. Government forces here have resorted to using U.S.-supplied helicopter gunships, World War II-model T28 airplanes, 105-mm howitzers, and armored personnel carriers.

Why the conflict in this province has escalated relative to other areas since Aquino came to power is much debated. Some analysts say it may be no coincidence that Cagayan is the home province of Defense Minister Juan Ponce Enrile.

The aim of the insurgents, in this view, may be to provoke Enrile into a harsh military response and thus exacerbate friction between him and the more dovish Cabinet ministers close to Aquino. These analysts said the assassinated mayor Baclig was a boyhood friend of Enrile's. Military sources said his body was mutilated after he was gunned down in an ambush in March.

The level of fighting may also reflect regional differences within the Communist Party of the Philippines and its armed wing, the New People's Army, some analysts say. The party in this area has a reputation for being more radical than elsewhere.

According to former rebels who have surrendered or been captured recently, the guerrilla leadership has told them that Philippine society cannot change under Aquino because the country remains dominated by the United States.

The former guerrillas also told of an unusually heavy regimen of ideological indoctrination in rebel camps in this region and harsh discipline marked by torture and executions of suspected informers. Three ex-rebels described purges in different NPA-held areas in which guerrillas or civilians were clubbed to death, ostensibly to save ammunition.

However, they also described what they called "military atrocities" -- mainly beatings and killings of villagers -- that drove them to join the rebels in the first place.

"There's a long list of military atrocities here," Aguinaldo conceded, "but there's also a long list of NPA atrocities." In this province, he estimated, "more than 5,000 innocent civilians have been killed since the NPA came here" in the 1970s. According to residents of Gattaran, about 500 villagers along the Dummon River were executed from 1979 until Aguinaldo established a base there in 1983.

"My unit alone already executed nine civilians since March," said Ka Lito, 27, who surrendered to Aguinaldo May 7 after two months in the NPA. (Ka is an honorific title used by Filipino peasants and adopted by the NPA to mean something like comrade.) He said three of the victims were farmers who were beaten to death with tree branches in March at Bolos Point on Cagayan's eastern coast after they were accused of being military informers.

Ka Lito said he completed a training course at the site in April along with 20 other new recruits, but that he quickly became disillusioned. Wearing a fatigue jacket, an ammunition belt and faded red sneakers, Ka Lito now carries an M16 in the service of Aguinaldo's irregulars.

Another former rebel, Ka Annie, 28, said she was captured March 27. She said she had been told by communist leaders that there would be no improvement under the Aquino government. "There's no change in the economic situation, but I believe that military atrocities have decreased since Cory [Aquino] took over," she said.

Ka Annie said she witnessed two NPA executions in 1984 near the town of Pudtol in neighboring Kalinga-Apayao Province. She said two men accused of acting as military guides "were interrogated and constantly tortured" before they were beaten to death with clubs.

Ka Tessie, 27, said guerrilla leaders never discussed a cease-fire or amnesty proposed by Aquino. She said she joined the NPA and became an armed "group organizer" because her father-in-law had been killed in custody by the military in 1982. She said she was captured May 23.

Aguinaldo, in pursuit of the NPA, clearly prefers to rely on his unit of about 100 Philippine Constabulary Scout Rangers and rebel "returnees." He said he now has about 50 former rebels with him, most of them living at a camp in an area he said was once among the most "rebel-infested" in the country.

In Aguinaldo's view, the rebels showed they had adopted a brutal new tactic in their May 27 ambush at Pateng Bridge on the outskirts of this town. He and survivors of the attack reported that the guerrillas had opened fire from houses by the road, forcing their inhabitants to remain inside to prevent them from alerting authorities.

Killed on the spot was patrolman Danilo Sarenos, 25. In addition to the police casualties, at least one civilian was reported killed in the exchange of fire.

A survivor of the ambush, Pvt. Andrew Tumbali, said the guerrillas used a megaphone to taunt the fleeing, outnumbered police to fight. He said the rebels then withdrew before government reinforcements arrived.

Although the police station in Gonzaga is less than a mile away, it responded slowly, eventually sending some policemen on a fire truck, Aguinaldo said. He said it was the second time in May that police riding in the same jeep had been ambushed while on a food-buying errand. On May 9, two policemen had been killed.

The day after the latest ambush, Aguinaldo relieved the reportedly drunken Gonzaga police station commander and the officer in charge of the field force company. He was absent at the time of the attack, along with about half the unit's members.

Members of the company complain of shortages of arms, ammunition and supplies. They live in a bamboo barracks behind shallow foxholes and crude fortifications of earth and bamboo staves that resemble big flower boxes. With only one fatigue uniform and one pair of combat boots issued to them, they perform their duties mostly in shorts, T-shirts and thongs, often looking more like rebels than do those of the NPA, who usually wear military fatigues while carrying out their operations here.

Pinned to a board in the barracks is a photo from a captured rebel knapsack showing an NPA commander clad in clean khaki overalls and a camouflaged jungle hat and proudly cradling a Soviet-designed Kalashnikov automatic rifle.

According to Aguinaldo and former rebels, 30 of the rifles, with four ammunition clips each, arrived in the province in late 1981 from Manila, where they had been smuggled in from abroad. The colonel said they had been purchased on the international arms market and had "passed through Syria."