The Cuban government demanded today that all the men who fled into the U.S. diplomatic mission here two days ago during a violent melee be handed over without conditions.

The Cuban demand creates an apparent deadlock in the U.S.-Cuban negotiations on the fate of the 387 Cubans jammed into the U.S. mission and sets the stage for prolonged talks that are likely to involve other, broader issues between Havana and Washington.

Sources familiar with the U.S.-Cuban negotiations of the last two days immediately drew a parallel with the U.S.-Iranian impasse and predicted, "This looks like a really long haul."

A State Department spokesman in Washington said the United States rejects the Cuban demand. "We do not agree with that position. . . . We are seeking a means to have all the Cubans currently within the U.S. Interests Section receive their visas," the spokesman said.

[In what they called a "separate decision," State Department officials also said yesterday that because of uncertain security arrangements, the United States is suspending the immigrant visa and refugee processing programs at the U.S. mission in Havana, effectively closing off legal avenues for Cuban immigration to the United States. The officials said, however, that the step would not affect the "sealift" operations that have been bringing thousands of Cubans to American shores.]

The United States maintains only a small staff at the interests section since Cuba and the United States do not have full diplomatic relations.

While the talks here have been shrouded in secrecy, Cuba today announced its position in the official Communist Party newspaper, Granma.

Because the American mission here "has no right whatsoever to grant asylum to anyone, its actions fall outside international law," the newspaper said. "The United States government has the obligation to put the antisocial element [inside] at the disposal of the Cuban authorities without conditions, because they provoked and attacked people in complicity with a foreign government."

Ironically, most of the men inside the U.S. mission already possess Cuban exit permits and only need U.S. clearance to leave the country. They were lined up outside the building Friday to get the long-delayed U.S. papers when the violent fight erupted.

By demanding the return of the men in connection with the violence, it was not clear whether Cuba intends to allow the men eventually to use the exit papers they already possess.

About 450 Cuban applicants for U.S. visas fled inside the U.S. building for security following the attack Friday by about 20 men wielding chains, pipes and clubs. U.S. officials have blamed the Cuban government for the attack and criticized the local police for not moving to stop it.

Nearly 60 of the refugees agreed to return home following the violence but 387 Cubans have stayed inside the seven-story mission building. Of these, 308 are men, the majority of whom are former political prisoners who served long sentences for counterrevolutionary activities." There are also 68 women and 11 children.

"The Cuban government is willing to give safe-conduct passes to the women and children," the official newspaper said, but the men can leave the building only "depending on their willingness to turn themselves in unconditionally to the Cuban government."

Until late Saturday, American diplomats and the Swiss ambassador talked with Cuban officials about a U.S. request to airlift the refugees inside the mission to the United States. In the absence of formal diplomatic ties, Switzerland technically represents U.S. interests here.

Cuban President Fidel Castro reportedly was seen close to the mission Saturday but it is not known whether he talked personally with American diplomats.

The first hints of difficulties came in Saturday's edition of Granma, which said in an editorial that other former political prisoners could leave via the port of Mariel, the departure of those inside the mission would have to be negotiated with the Cuban government.

Well-informed sources said that more hints of trouble came during the talks of Cuban officials stalled or presented new conditions to the U.S. request.

U.S. diplomats here have received an order from Washington not to discuss any aspect of the talks with the press.

Before the clampdown, the Americans reached by telephone inside the mission, which now has a tight Cuban security cordon around it, sounded moderately optimistic, saying they expected a Cuban answer soon.

Four Americans consular officers and five U.S. immigration employes who have been on temporary duty here have worked around the clock since Friday to issue documents for entry into the United States for all those inside.

By Saturday night, the paperwork for all inside reportedly was ready.

The situation for the refugees, including the 14 wounded, inside the building was described by American diplomats as "satisfactory."

The crowd, quiet and disciplined, was organized into food and cleaning committees and spent much of Saturday watching videotapes of the World Series.

"They really liked this.It [baseball] is Cuba's national sport," one diplomat said.

The Cubans also had formed a little nursery for the children.

The refugees had been given sandwiches and milk, for which they paid one Cuban peso, the equivalent of $1.30, one American reported.

Among the men in the mission are several well-known former prisoners who actively participated in the fight to Overthrow Castro in the early days of the revolution, some of them reportedly in complicity with the U.S. Central Intelligence Agency.

One of the better-known men reportedly is Jaun Enrique Morejon, the nephew of Huber Matos, a famous prisoner who fought with, Castro in the prerevolutionary days and was released last year.

According to a foreign correspondent based in Havana, Morejon was one of those who jumped over the fence of the Peruvian Embassy one month ago when more than 10,000 people stormed the embassy compound.

At the time Morejon was wounded in the foot by a bullet. Morejon then learned that he would not be able to leave Cuba via the refugee port of Mariel but would have to follow the established route for former political prisoners and get exit papers from the American mission.

Morejon told the correspondent he had served a long term for participating in a plot to kill Castro's brother Raul.

In another policy reversal, the government announced in Granma that from now on political prisoners could leave via the sea bridge at Mariel to Miami.

The paper also said that now that weather conditions have improved, the exodus from Mariel can resume. It was halted for several days during a heavy storm.The paper said however, that the safety of the boats is a matter of importance and weather conditions would determine the departures. About 1,750 boats are waiting in the port of Mariel where a hugh backlog is expected to delay the departure of the late arrivals for weeks.

Washington Post staff writer Warren Brown reported from the State Department:

U.S. officials said the suspension of activities in Havana was prompted by Friday's attack.

"The decision to suspend immigrant and refugee processing is a separate decision taken because of the apparent unwillingness of the Cuban government to provide security for Cubans conducting normal business at the mission," a State Department spokesman said.

The spokesman said the U.S. intends to process all the Cubans currently within the mission.

About six State Department officials who handled the immigrant and refugee programs at the U.S. diplomatic mission will be brought back to Washington, department officials said.

"This does not mean "we're breaking relations with Cuba," another State Department official said.

The officials said Americans with other duties will remain at the diplomatic mission and that Cuban government officials will still be allowed to travel to the U.S. on nonimmigrant visas.