Lying in the tall grass between the city's modernistic concert hall and calm Lake Managua, the young men appeared to be sleeping. A closer revealed that each wore a crude cloth blindfold and had a bullet hole in his head or chest.

Today there were nine, freshly killed and still undiscovered by the vultures that cruise over the capital. There is a different group, sometimes larger but rarely smaller, practically every day. Several yards away, the ashes of a large bonfire are mixed with bones.

President Anastasio Somoza says the National Guard does not carry out summary executions. Yet similar group of young men -- shirtless and blindfold -- are seen daily being marched, single file with their hands on each other's shoulder, through Managua's central jail compound.

Early yesterday morning three pickup trucks full of blindfolded youths were seen being driven away from the state security headquarters behind Somoza's bunker office.

Because of these actions, and the National Guard's long history of being known as Somoza's personal henchmen, many Nicaraguans doubt that the Guard will have a place in a new government here.

The future of the National Guard is perhaps the most crucial issue holding up the transition of power from Somooza to a guerrilla-back provisional government junta.While the junta has said that "many perhaps the majority" of Guard soldiers can be retained in a new army led by Sandinista National Liberation Front guerrillas, the junta has insisted that the National Guard itself be disbanded, and that officers believed guilty of "crimes against the people" who do not leave the country with Somoza must be tried and punished.

The junta, based in Costa Rica, has been under strong pressure from the United States both to change its structure and to preserve the National Guard. Now, apparently as a result of U.S. diplomatic persuasion, a number of other Latin American governments have joined that effort.

Junta representives said they were informed yesterday that, if they do not give in, international support and supplies for the Sandinistas in their civil war against Somoza and the National Guard will be "made more difficult," and the United States will continue to withhold Somoza's resignation.

Calling the pressure "blackmail," junta foreign minister Miguel D'Escoto said "they are trying to bargain with the blood of our people. It can only result in a prolongation of civil war and anarchy."

Although the junta did not issue a formal response to the U.S.-Latin proposal, it spoke last night over an internal radio network to Sandinista commanders throghout Nicaragua. Their rejection of the plan, D'Escoto said, was unanimous.

Junta leaders were called in by Costa Rican President Rodrigo Carazo and were telephoned by former Venezuelan president Carlos Andres Perez as part of the U.S. pressure, sources said. Both Latin leaders had been strong supporters of the Sandinistas before the junta's refusal to accept the U.S. proposal.

In the past week, the governments of Venezuela, Costa Rica, Colombia, the Dominican Republic and Panama have been visited by high State Department officials.

A little more than a week ago, the United States let it be known that Somza had decided to resign if U.S. diplomats guarantee preservation of the Guard. The United States feared that racial elements within the Sandinistas would run rampant in a new government without what Somoza called "the National Guard as a counterforce." That fear apparently was expressed to the other Latin American governments, along with American assurances that Somoza's resignation was "in the U.S. pocket," under the proper conditions.

But while the United States wants more moderate members added to the junta, its current members say the somewhat delicate existing balance of two political moderates and three leftists was achieved only after strenuous negotiations.

"If we give in," D'Escoto said "the junta will have signed its own death warrent."

The junta fears that neither extensive changes in its composition nor concessions made to the National Guard will be accepted by Nicaraguans who have sacrified lives and livelihoods for the Sandinista revolution.

He said that Nicaraguan moderate opposite groups, members of which the United States has approached as possible additions to the junta, had shown no interest in preserving the National Guard and had given their support to the existing junta.

Following Somoza's acknowledgement last Friday that he has given his resignation to the United States, the Superior Council of Private Enterprise, Nicaragua's most prestigious business group, condemned both Somoza and the United States for "continuing to bomb Nicaraguan cities" while trying to work out what they consider a satisfactory government.

Despite his announced intention to resign, Somoza has given no indication he will call off the fighting until he leaves. As for the National Guard, high-level officers have said privately they have no intention of making a truce with their enemy and see little possibility of forming a new army with the Sandinistas.

Nicaragua's archbishop, Miguel Obando y Bravo today released a statement read in the country's Catholic churches calling on combatants to remember "that they will have to answer for their actions during the war."

Referring to continuing National Guard bombing attacks, the archbishop condemned "the indiscriminate destruction of entire cities . . . and their inhabitants" as a "crime against God and hunanity."

He also condmned "searches of churches, places of refuge and hospitals" as "criminal" -- an apparent reference to a Friday night National Guard attack against Managua's International Red Cross headquaters where hundreds have taken shelter. Peppering the building with machine gun fire, the National Guard wounded three people and dragged away seven young men. CAPTION: Picture 1, Red Cross workers inspect the bodies of nine men who had been blindfolded and shot. AP; Picture 2, A Sandinista guerrilla rides atop a truck in the provincial capital of Esteli.