Central America feels pressure to talk with opposition

Across Central America, embattled governments are fidgeting under new international pressure to try to resolve their differences with rebel opposition groups by peaceful means.

The region's most powerful and influential neighbors - Mexico, Venezuela, and the United States - are turning the screws on them once again, worried that the region's wars are spreading.

Reaction to this pressure is, as with similar diplomatic efforts last winter and last year, mixed. Nicaragua's leftist Sandinista government and Salvadoran leftist and moderate rebels have criticized some of these international efforts - particularly those of the US - but a flurry of proposals by the combatants themselves is viewed as a hopeful sign by some Latin America observers.

El Salvador's government is feeling international pressure most strongly. This week the US sent Undersecretary of Defense Fred C. Ikle to El Salvador to protest recent abductions of top leftist politicians and labor leaders and the Salvadoran government's intention to try those officials on charges of terrorism.

Mr. Ikle is expected to suggest firmly that US military aid will be curtailed , perhaps ended, if deaths and abductions of civilians and opposition politicians by what appear to be suspicious means continue. The US will also protest the Salvador judiciary's failure to take action against two national guard officers accused of ordering the murder of two US land-reform consultants and a Salvadoran land-reform official last year.

These human-rights issues appear to be contributing to developing splits in the right-moderate coalition government - and are viewed as one reason the US is pushing anew for a negotiated settlement of the civil war. A fragile government, some say, may be more willing to yield to pressure.

Almost simultaneous with Mr. Ikle's arrival in San Salvador, Salvadoran rebels based in Mexico City issued a new proposal for negotiations with the government. It called for ''direct dialogue without prior conditions'' between the parties, and thus is a significant departure from previous proposals that outlined what issues must be addressed. Analysts say the rebels may be timing the new proposal to coincide with a guerrilla offensive - in effect bargaining from a position of strength.

At time of writing, the government had not formally responded to the left's proposal. But powerful right-wing leader Roberto d'Aubuisson responded immediately, rejecting negotiations. Talks have traditionally been stymied because the government and left have taken different views of the proper role of the left. Moderates in the government have wanted to bring the left into the electoral process; the guerrillas wanted an immediate, shared role in government.

Most analysts say peace throughout the region depends essentially on what happens in El Salvador. But fighting in Nicaragua and Guatemala, and political tensions in Honduras, Costa Rica, and Panama are also viewed with alarm.

Mexico and Venezuela are trying again to work out a settlement in El Salvador , and to convince Nicaragua and Honduras to scale down tensions between them and end battles along their border. (Nicaraguan rebels based in Honduras are fighting the Nicaraguan army along the border.) Mexico and Venezuela are quietly suggesting some sort of formal cease-fire up and down Central America - perhaps using the Organization of American States as the vehicle for a cease-fire.

Nicaraguan rebels, joined now by Miskito Indians, are stepping up strikes in Nicaragua. Nicaragua has accused the US of spending millions to arm the anti-Sandinista guerrillas, and last spring endorsed plans for talks with the US in Mexico under a formula proposed last February by outgoing Mexican President Jose Lopez Portillo. Mexico and Venezuela have both asked the US to end aid to Nicaraguan rebels.

Guatemala - under fire from international human-rights groups for alleged indiscriminate killings of thousands of peasants - said recently that it is setting up its own human-rights commission that will prove its accusers are wrong. Leftists, recently joined by Indians, are said to be stepping up opposition to the government, whose army is responding by hunting down rebels in villages.

Cuba has also quietly urged both the guerrillas in El Salvador and the Sandinistas in Nicaragua to keep searching for accommodations with their enemies and the Reagan administration.