Latin American leaders yesterday appeared to be moving toward endorsement of a U.S. call for Nicaraguan President Anastasio Somoza to resign, but it was unclear last night whether they would support other U.S. proposals for ending Nicaragua's civil war.

At Thursday's opening of an emergency meeting of the Organization of American States. U.S. Secretary of State Cyrus R. Vance called for Somoza's replacement by a temporary "government of national reconciliation."

In a formal six-point proposal, Vance also urged the 27-nation hemispheric body to seek a cease-fire, halt arms shipments to the contesting Nicaraguan factions, send an OAS delegation to assist in the political transition and consider the need for an inter-American peacekeeping force in Nicaragua.

But following several hours of private negotiation yesterday the Latin American countries appeared to be resisting those features of the U.S. plan that could be construed as intervention in a member state's affairs.

In particular, it seemed clear that the peace force suggestion stands little chance of being adopted. The Latin countries also seemed cool to the idea of injecting and OAS delegation or other OAS presence into the Nicaraguan struggle.

U.S. officials have said privately that their priority goals at the meeting are to get the OAS on record as favoring Somoza's resignation and to put an OAS presence capable of dealing with the feuding Nicaraguan factions into that country as soon as possible.

As a result, U.S. lobbying efforts were concentrated last night on trying to overcome Latin American objections to dispatch of an OAS delegation.

U.S sources conceded that the peace force proposal has no support and said it had been offered only out of a belief that it was something the OAS should discuss.

But some U.S. sources said privately that the peace force concept had been the idea of President Carter's national security affairs adviser, Zbigniew Brezezinski, and his National Security Council staff. They said it had been included in the U.S. proposal at White House insistence, despite warnings by the State Department that it would trigger and adverse reaction from the Latin Americans.

Some Latin American sources said last night the proposal may have been a tactical mistake on the part of the Carter adminstration. According to these sources, the idea of a peace force, with its overtly intervnetionist connotations, had heightened Latin American sensitivity to the idea that any OAS delegation could be considered interventionist, and made the delegation plan more difficult to accept.

Adding to the U.S. problem is the sympathy felt by many Latin American democratic governments for Somoza's foes, the guerrillas of the Sandinista National Liberation Front, and their suspicion that the U.S. plan is designed to keep the Sandinistas from winning power.

The Carter administration is known to be skittish about the possibility of a Sandinista takeover because the movement contains strong Marxist, pro-Cuban elements. Washington hopes instead for a broadly based interim government that would balance the Sandinistas with more moderate political forces.

Late yesterday, 13 of the OAS nations introduced a counter resolution that paralleled the U.S%. PROPOSALS FOR AN END TO THE SOMOZA REGIME, INSTALLATION OF AN INTERIM GOVERNMENT ND MOVEMENT TOWARD FREE ELECTIONS. TO BE ADOPTED AS OFFICIAL OAS policy, the resolution requires the support of 18 members.

The new resolution did not pick up the U.S. call for an OAS delegation to go to Nicaragua. Instead, it urged "the member states to conduct negotiations that are within their scope . . . scrupulously respecting the principle of non-intervention."

Despite that difference - and despite other language that appeared aimed at giving the Sandinistas a dominant role in an interim government - U.S. sources professed to see in the new resolution a possible basis for compromise, particularly if the sponsors could be induced to accept the concept of a special OAS delegation.

But the uphill struggle the U.S. proposals face, was underscored in yesterday's debate when a Sandinista spokesman denounced the U.S. plan as "an attempt to violate the rights of those Nicaraguans who have almost succeeded in throwing off the Somoza yoke."

The Rev. Miguel D'Escoto, a Nicaraguan Maryknoll priest, addressed the meeting over U.S. objections after Panama - which supports the Sandinistas - accredited him as part of its delegation.