MEXICO CITY, JUNE 27 -- A new round of peace talks between the government of El Salvador and leftist guerrillas has produced hope that after a decade of bloodshed the country's civil war may be headed toward resolution.

Four previous attempts since 1984 to end the fighting through negotiation ended in failure, with each side accusing the other of intransigence and bad faith. When talks collapsed last fall, an all-out offensive by the leftist Farabundo Marti National Liberation Front followed in November -- an offensive that claimed at least 2,000 lives in some of the most vicious fighting of the war.

The latest dialogue -- which recessed here Monday after a week at the bargaining table in the central Mexican resort of Oaxtepec -- suggests that much has changed since the fall and that for the first time the two sides may be more interested in reaching an accord than in scoring propaganda points.

Although no agreements were reached, United Nations mediator Alvaro de Soto, in a statement seconded by government and rebel negotiators, said the talks had "produced movement in this direction that is unprecedented in the history of contacts between the government and the FMLN."

That assessment is all the more promising given that the six days of talks focused on the thorniest issue confronting the negotiators: reforming and restructuring the country's 56,000-member army and security forces.

El Salvador's armed forces, trained and financed by the United States, have never been firmly under civilian control. Critics say that, as a virtually autonomous force in Salvadoran society, the military is primarily interested in maintaining its privileged position. Individual colonels preside over fiefdoms, corruption is rampant, and loyalty is rewarded over respect for human rights.

The current round of talks, scheduled to resume July 20 in Costa Rica, marks the first time the two sides have conducted in-depth discussions about the future of the armed forces. In an atmosphere that de Soto called "free of rhetoric," such talks suggest that both sides see the makings of a deal.

"The negotiations are open," said Schafik Handal, one of the five top FMLN commanders. "That's what's new."

The new flexibility in the talks is probably driven by shifts outside the country that have suggested to both sides that they must bargain for the best deal now because in the long term their positions may weaken. The guerrillas were stunned by the electoral defeat of their Sandinista allies and arms suppliers in Nicaragua and are nervous about the economic crisis closing in on Cuba, their last remaining patron in the hemisphere.

The army is just as anxious about political tremors in Washington, where even some conservatives are questioning the wisdom of pumping $85 million of military aid annually into a conflict that is coming to appear strategically illogical, given the demise of Communist regimes around the world. Proposals in Congress to cut aid to El Salvador's armed forces by half are now under consideration.

By concentrating at the outset on the most difficult issue -- military reform -- the negotiators ignored the advice of key diplomats and church officials, who argued that the talks should begin with small-ticket issues whose relatively easy resolution would build confidence in the early stages of the dialogue.

However, most analysts agree that changes in the armed forces are probably the critical factor in pursuading the FMLN to agree to a cease-fire and to make the transition from armed insurgency to political party.

The bulk of the rebel demands involve shake-ups in the armed forces. The government has so far produced no comprehensive response, but Col. Mauricio Vargas, the army representative on the government's negotiating team, acknowledges the need for what he delicately calls the "modernization and evolution" of the armed forces.

Perhaps the toughest of the guerrilla demands is vigorous prosecution of four notorious human-rights cases in which the army has been implicated: the slaying of six Jesuit priests during the November offensive; the 1980 assassination of Archbishop Oscar Romero; the bombing of a labor-union headquarters last October that left 10 dead; and the killing of leftist political leader Hector Oqueli Colindres, who was slain in Guatemala in January, apparently by a Salvadoran death squad.

{The Associated Press reported that an arrest warrant was issued today for an army officer accused of destroying evidence in the killing of the six Jesuit priests, their cook and her teen-age daughter. The warrant charges Lt. Col. Camilo Hernandez, an executive officer of the elite Belloso Battalian, with destroying the duty logs of troops accused in the case.

{The wanted officer is the former assistant director of the military college where the troops were stationed. The director of the college, Col. Guillermo Benavides, three lieutenants and five enlisted men have already been charged with murder in the case.

{Special correspondent Douglas Farah reported that younger military officers have expressed anger that the lieutenants were being held, contending they were unfairly singled out for prosecution to protect superior officers involved in the killings.}

No Salvadoran army officer has ever been convicted in a human-rights abuse case, despite widespread evidence of army involvement in the killings of thousands of civilians over the course of the war. The guerrillas insist that a negotiated settlement must put an end to what they refer to as the army's "impunity."

However, the government has pointed out that the guerrillas themselves are responsible for murders and other human-rights abuses, such as the killing of the country's attorney general last year. "In the end, if you don't have an amnesty for almost all cases, it's going to be very difficult {to achieve a settlement}," said a western diplomat.

The rebels also call for "purifying" the armed forces by firing officers who have been involved in human-rights abuses; dissolving the elite Atlacatl Battalion, a counterinsurgency unit linked to the killing of the priests; installing a civilian as defense minister; and putting an end to forced recruitment.

Government negotiators have been careful not to reject the guerrilla proposals out of hand, even though some of them would be certain to anger military and hard-line rightists in the government. "Before, they didn't take us seriously, and they wanted to win at the table what they couldn't win on the battlefield," said FMLN commander Nidia Diaz, a rebel negotiator. "Now they're taking us seriously."