HAVANA, Aug. 6 - Cuban authorities today paraded six alleged counterrevolutionaries, said to have been sponsored by the United States, before delegates attending the Latin-American Solidarity Conference here.

The authorities accused the United States of having landed 'the group on the island to prepare for the assassination of Premier Fidel Castro and other Cuban leaders and to organize armed uprisings in Cuba.

Observers interpreted the presentation of the alleged agents which lasted more than three hours, as a reply to charges of Venezuela and the Organization of American States that Cuba is subverting other countries.

The Cuban authorities said four alleged Central Intelligence Agency men were captured on July 18 after landing at Bahia Honda, 100 miles west of here, from Florida with a collection of arms, including submachine guns with silencers and cyanide bullets.

The four, all Cubans, together with two other alleged counterrevolutionaries, including one who said he was captured on Saturday, were presented to a special session of the meeting, which ends Tuesday.

The alleged agents told the assembled, delegates and journalists that they had been trained and paid by the Central Intelligence Agency, and that their principal aim was to develop a network within Havana and other cities as a first step toward carrying out acts of terrorism and assassinating Cuban leaders, including Premier Castro.

Two radio transmitters and 140 pounds of plastic explosive, said to be their equipment, were also put on show.

The six prisoners, dressed in olive-green uniforms, appeared relaxed and frequently smiled as they confessed to the charges before a panel of three security officers who interrogated them quietly.

Stokely Carmichael, a leading black power spokesman in the United States, was in the audience.

The six, all in their late 20's or early 30's, left Cuba in the early years of the Castro regime, 1960 and 1962, they said. One of them, Alberto Laucerica Diaz, said that after the first stage of developing contacts in the cities, assassination attempts were to be directed against Government leaders.

"The prime ultimate objective of all these plans was the physical elimination of Fidel Castro," he added.

The uniforms they wore were allegedly those in which they had been captured. They were similar to Cuban Army uniforms but had special shoulder tabs. Another member of the group, Jose Roy Rodrigues, said he was recruited by the Central Intelligence Agency in 1963 and trained in radio operating and weapons handling. He said one of his trainers was a former German Gestapo official named Franz.

He said they had been trained in security houses on the outskirts of Miami. Roy, who said he had participated in previous missions, said the group left from a place called Flamingo, Fla.

A third member, Franciso Avila Azcuy, said they had potassium cyanide bullets "to kill," but that there had been no one specific in mind.

A fourth member of the group, Pablo Garcia Roqueta, said he was trained by the Central Intelligence Agency in Puerto Rico.

A fifth was wounded when he resisted arrest.

The Bahia Honda group was allegedly captured after two members of the band gave themselves up to the authorities. It was not clear whether these two were among those presented today.

Vicente P. Gonzalez Mygoyo said he was captured in Matanzas, east of Havana, yesterday while on a mission to take certain people out of the country. He did not elaborate.

He sipped water as he explained that he had been on three previous missions to Cuba and drew on a large map on the wall routes he had taken from Florida, around western Cuba, to the south coast of the island.

A sixth person, Jose Rabel Nunez, who was allegedly, captured some time ago, also was presented and said he had worked for the Central Intelligence Agency.

After the official questioning, the prisoners answered questions put to them by journalists, but little additional information was brought out.

HAVANA, Aug. 6 (AP) Jose Rabel Nunez, who was identified today at the Latin-American Solidarity Conference as a former official of the Agrarian Reform institute, said he defected in 1962 in an airplane and was met in Florida by United States officials who took him to Washington for questioning. He said he was paid $650 monthly plus expenses, as a Central Intelligence Agency agent and that more than 400 organizations in the United States worked for the C.I.A. Rabel, only one of the six who spoke English, said he had come to Cuba to get his family out.

A Cuban exile named Jose Richard Rabel was reported to have been arrested in Havana in September 1965, during an attempt to rescue his wife and three children and take them out of Cuba.

He had once been a spearfishing companion of Premier Castro. From 1960 to 1962, he ran the rural housing program, one of the Premier's favorite projects.

MIAMI, Aug. 6 (AP) - The militant anti-Castro exile group, Second Front of Escambray, said here today the men captured in Cuba were guerrillas from its organization.

Andrea Nazario, secretary general of the group, said the expedition left for Cuba nearly four weeks ago.

"They were going to infiltrate Cuba on a mission of subversion and guerrilla warfare and were going to join up with patriots inside Cuba," Mr. Nazario said.

Special to The New York Times

WASHINGTON, Aug. 6 - A spokesman for the State Department refused to comment today on Cuba's assertion that she had captured a group of armed counterrevolutionaries sponsored by the United States.