KOMPONG SPEU, CAMBODIA — `TO beat the Khmer Rouge,'' says Cambodian soldier Hem Pham, ``we must act like Khmer Rouge.'' Long months in hostile jungles, bloody ambushes, night spying on peasants, laying booby traps - not to mention lousy food, meager pay, and mosquitoes - these are the rigors needed to match the fire of one of history's most tenacious and nastiest guerrilla forces.
The Khmer Rouge, the strongest of three resistance groups in Cambodia, are meeting their match with the likes of Hem Pham, a member of an elite unit known as A-3.
Attired in dark brown clothes, the A-3s specially trained commandos are the shock troops for a communist regime in Phnom Penh that stands alone against a guerrilla resistance following an end to Vietnam's decade-long occupation in September.
With peace talks suspended, a test of strength is in full force on the battlefields of Cambodia, as both sides proclaim victories along the border with Thailand.
The A-3 fighters, numbering more than 40,000, are officially called the Armed Forces Reconnaissance Forces. They operate in small units of three to five men, carrying only a flashlight, mosquito net, hammock, food rations, AK-47 rifle, and an occasional B-40 grenade launcher. Most are deployed along the long border with Thailand where the Khmer Rouge and two noncommunist guerrilla groups enter Cambodia from safe havens in Thailand.
Hem Pham is a member of an A-3 unit of about 60 men in a district of Kompong Speu province just an hour's drive southwest of Phnom Penh. His unit's chief target: an estimated 90 Khmer Rouge guerrillas hiding in the province's mountains.
``We wait long weeks in the jungle,'' says Mr. Hem. ``We were chosen for our combat spirit and our strength.''
And, it can be added, their loyalty to the ruling Marxist-Leninist party. Soldiers in Phnom Penh's regular forces often desert or defect amid Cambodia's political confusion. A-3 was established to ensure at least one stable, effective force.
The unit's short-hand name comes from the month it was founded - March - three years ago.
``Our Army is better than the Vietnamese Army at attacking the Khmer Rouge,'' says Toch Yoeun, a top official in Kompong Chhnang province, about 100 miles north of Phnom Penh. ``After all, many of our officers are former Khmer Rouge. We know their tactics.''
A-3 recruits receive three months training in Phnom Penh and in the eastern province of Kompong Cham, near Vietnam, where there is jungle terrain.
``We have to counter guerrilla tactics with guerrilla tactics,'' says Cham Prasith, an aide to Prime Minister Hun Sen. ``A-3 is more efficient than the regular military. They [the A-3] are in the jungle.''
Many leaders in the present regime, including Hun Sen, defected from the Khmer Rouge in the mid-'70s, and sought Vietnamese help to throw out the Khmer Rouge.
A-3 works to place spies inside Khmer Rouge ranks. ``If a major attack on a city is planned, our spies can inform us almost immediately,'' Hem says. ``The Khmer Rouge are peasants by day, fighters by night. We need good intelligence.''
In nearly 11 years of fighting since the Khmer Rouge were ousted, about 20,000 of Phnom Penh's forces have died, says Prak Sokhonn, deputy editor of the Army newspaper. About half of them died from malaria, he adds.
For the estimated 25,000 to 35,000 Khmer Rouge fighters, launching big offensives inside Cambodia is difficult. ``Their strength is like a rubber band,'' says Hun Sen. ``If they stretch too far, they break.''
Guerrillas working under Prince Norodom Sihanouk, the former ruler, are setting up a spy network to counter an election expected early next year, say Phnom Penh officials, and the Khmer Rouge are making new efforts to coax soldiers to defect.
In 1989, the Khmer Rouge stepped up the killing or kidnapping of top village officials - in one province alone, more than 100 were killed or kidnapped.
A kidnapped chief is forced to write statements saying he will not work for the government. The statement is then distributed to the people to discredit him.
After Vietnam's troop pullout, the Khmer Rouge strategy also appears to target key industries. Small units hit a Thai-supported cement plant in Kampot province on Oct. 13, killing three workers. And during the same week, a Soviet-backed rubber factory in Kompong Cham was attacked.
``They want to cut our new economic links with Thailand,'' Mr. Cham says. Such attacks may also be planned to slow a spurt of economic activity and to scare potential foreign investors and tourists.
One effect of guerrilla attacks is that it keeps the Phnom Penh regime dependent on Vietnam. Many exports will continue to go through Ho Chi Minh City or out the Mekong River, rather than through Thailand.
The Khmer Rouge survive by means of coercion, guns, and promises. One tactic is to warn peasants to store rice because a big battle will start soon. The guerrillas then steal the rice. They also go to markets and pay exorbitant prices for rice, leading farmers to hoard and disrupt supplies.
``They survive mainly by their subsidy from China,'' says a Vietnamese diplomat in Phnom Penh. ``And they have such a good life on the border that they are having difficulty getting people to the front. They will try to achieve something spectacular to show their strength. But can they keep what they conquer? That's a big question.''
Phnom Penh officials say that the Khmer Rouge have tried to take big offensives in recent weeks and create ``liberated zones'' because the Thai military has advised them to leave Thai soil soon. A new Thai leadership wants more trade with Cambodia.
Desperate for food supplies, the Khmer Rouge may be trying to reach the rich fish and rice areas around Cambodia's great lake, the Tonle Sap. Even though they have small units near Phnom Penh, they have been unable to penetrate the ``red shield,'' an outer perimeter of defense.
One reason is that three divisions of A-3 units stand guard on the capital's northern flank.
Another is steady improvement of the Army, estimated at more than 65,000. Military ranks were introduced just this year. And medals have begun to be handed out to ``heroes,'' defined as anyone who kills more than 30 of the enemy. Massive Soviet aid also boosts the war effort.
``We will continue to receive Soviet aid until the other side stops receiving equipment,'' Cham said. He added that Soviet assistance this year was about the same as last year.