The Cuban government today disputed President Reagan's charges of both the numbers and the assignments of Cubans in Grenada prior to Tuesday's invasion, as well as U.S. charges that large munition stores found near the island's Cuban-built airport were intended to take over Grenada and turn it into a base for exporting revolution.

"It is ridiculous to accuse the victim of an aggression of trying to arrange to protect itself," Deputy Foreign Minister Ricardo Alarcon said at a news conference here today.

Meanwhile, official silence continued over the question of when more than 600 Cuban prisoners said to be held by U.S. forces in Grenada will be returned here, as well as over the number of Cuban casualties in the fighting.

The Cuban government called together the resident diplomatic corps here for a meeting this afternoon in which, sources said, the diplomats were told that Cuba intends to take the Grenada situation to the U.N. General Assembly. A majority vote early this morning in the Security Council approved a resolution deploring the invasion, but the measure was vetoed by the United States.

The diplomats also were told that Cuba would refuse to recognize any "puppet government" installed by forces occupying Grenada.

In his news conference today, Alarcon sidestepped the question of who had supplied the caches of warehoused arms found by U.S. troops near the airport site on Grenada's southwestern tip, saying they were "probably for the use of the Grenadan militias."

Reagan's charge in a speech last night that the weapons were deployed for the Cubans themselves was "a big lie," he said. "I don't want to be rude, but in his statement he told several big lies."

While U.S. officials said today that the number of Cubans on Grenada was found to be as high as 1,100, Alarcon said "the total number of Cubans--every person born in Cuba and presently in Grenada--does not exceed 790."

In an earlier interview, Alarcon said that "it is true that there were very many construction workers" building a commercial airport that the Reagan administration charged could be used as a Cuban-Soviet air base.

"But it was an extremely complicated engineering project that required landfill and other technical things that the Grenadans, with little construction experience, did not know how to do." In his news conference today, Alarcon said that the project was a civilian one for which "there was no reason for the workers to be assigned to a military department."

According to a diplomatic source whose government has cordial ties with Cuba, however, it is unlikely that such a technical project would have been undertaken without the advice of Cuban military engineers who, he said, are the most highly qualified here.

Meanwhile, despite attempts by two outside governments to mediate, the return of Cuban prisoners appeared to stall. Early reports that some of the prisoners might be brought home aboard a regularly scheduled Cubana flight from Barbados were quashed when, the Cubans said, the plane was refused landing permission at the Barbados airport.

Alarcon said earlier that the dead and wounded would be flown in, and that the other prisoners would be returned on a merchant ship, the "Heroic Vietnam," that had been off the Grenadan shore when the invasion took place. The ship is now heading to harbor in nearby Trinidad to await a resolution of the issue, he said.

Alarcon said that the government in Havana has been able to reestablish contact with its ambassador, Julian Rizzo, in Grenada, but that U.S. forces there still had not contacted Rizzo concerning the repatriation of prisoners.

Neither the Cuban nor U.S. governments yet have released figures on the number of Cubans known to have been killed since the invasion began, but rumors spread here that the number was likely to be high. Although the total number of Cubans that were on the island at the time is disputed, at least 200 or so remain unaccounted for by all tallies.

Alarcon said that he had no knowledge of possible Cuban resistance that U.S. officials have said continues in the Grenadan hills. Although he said "there is a lot of fighting going on" still, he said Cuban diplomats in Grenada had been unable to make their own determination of whether Cubans were involved since "there recently have been some limitations on the movements of the diplomatic corps" on the island.

The Cuban government yesterday made public an offer by Spanish Prime Minister Felipe Gonzalez and Colombian President Belisario Betancur to mediate arrangements for the return of the Cuban prisoners. Sources close to the Spanish Embassy here reported today that there had been unexpected difficulties in making the transfer arrangements "which cannot be discussed."

Alarcon said he had been in touch with the Colombian intermediary this afternoon.

Alarcon expressed disbelief of official U.S. accounts for the delay of a message informing Cuba of the invasion. Cuba said it arrived after the invasion occurred.

He said that there was a "curious contrast" between diplomatic messages that talk about ending hostilities and messages that "reach us a couple of hours after our people were smashed, according to the information we had."