MAYANMARZ : Army’s Divide-Conquer Plan Turns Tide Against Guerrillas : Junta exploits religious differences to gain advantage over Karen rebels, who retreat into Thailand after two major losses.

SINGAPORE — The military government of Myanmar appears to have finally turned the tide against a rebel movement fighting one of the longest-running insurgent wars of modern times.

Myanmar, formerly known as Burma, has apparently adopted a divide-and-conquer strategy to get the upper hand over the Karen guerrillas, who are widely regarded as extremely tough adversaries.

The Karen make up one of the largest ethnic groups scattered along Myanmar’s eastern border. They have been fighting for their independence from Myanmar since the nation’s early days of independence from Britain in 1948.

The military junta, known as the State Law and Order Restoration Council, or SLORC, has apparently managed to exploit religious differences between the leadership of the Karen National Union--the main opposition group, which is primarily Christian--and a group of union followers who are primarily Buddhist. A small portion of the Buddhists appear to have defected to the government’s side, taking along details of defense works and mine fields leading to the guerrillas’ camps along the border with Thailand.

The Myanmar army has received massive amounts of modern arms from China in recent years--including warplanes, helicopters and artillery--and has deployed the new firepower in the campaign to dislodge the Karen.

The most devastating loss was the main Karen base at Manerplaw, which fell to the army on Jan. 26. More than 100 artillery shells landed in the camp before the Karen withdrew across the river into Thailand after setting their homes ablaze.

Manerplaw had not only been the Karen base of operations for more than two decades. It also provided shelter to students and other opposition leaders who became outlaws when the military came to power in 1988. These included members of the National League for Democracy, which won a landslide election victory in 1990 that the military refused to accept.

The second blow fell on the Karen last month, when a frontal assault on their last major base at Kawmoora forced the guerrillas to abandon the site without much of a fight. It became clear that dissident elements could infiltrate the camp’s defenses, and a strategic decision was made to abandon the base.

The Karen tried to put a brave face on the loss, saying they would return to guerrilla warfare inside Myanmar. “We have only lost the place,” said Nah Kaew, a Karen National Union official. “We will continue the struggle.”

Thailand has managed to remain fairly neutral in the fighting between Myanmar and the Karen. It has allowed any Karen to enter Thai territory unarmed and has refused permission to the SLORC army to cross onto Thai soil in pursuit of the guerrillas.

Initially, it seemed as if the fighting might be causing friction between Yangon and Bangkok, because two high-level visits were canceled without explanation. Thailand has been leading efforts with the Assn. of Southeast Asian Nations, or ASEAN, to move closer to Myanmar with what it called “constructive engagement”--a belief that increased trade and human contacts lead inevitably to the liberalization of a regime.

Doubts about a split between the two countries were dispelled, however, when SLORC Secretary Tin Oo paid an official visit to Bangkok late last month.

There is speculation among diplomats that the SLORC victory may provide the leverage to force the Karen to the negotiating table to reach a peaceful settlement of their demands for autonomy. Talks have been taking place at a low level in Bangkok, but there has been little room for compromise on either side.