HAVANA, CUBA, JULY 26 -- President Fidel Castro, describing a hostile world that takes its orders from Washington, today vowed to continue defying his enemies no matter how dire Cuba's economic hardship becomes.

"There's no force from the north or from Europe that can make Cuba kneel, that can dictate to Cuba," the Cuban leader told several hundred thousand cheering people in Havana's Plaza of the Revolution.

In a speech marking the 37th anniversary of his daring attack that launched the Cuban revolution, Castro delivered a frank, at times bitter, appraisal of the forces arrayed against this Caribbean island of 10 million people. But he vowed that despite the daunting challenges, capitalism will never return to Cuba "as long as there is one single revolutionary, one single patriot in this country."

The 63-year-old Cuban leader delivered his speech standing above an enormous banner bearing the word "Socialism." He spent nearly half of the three-hour address in a rambling chronology of the diplomatic crisis that has gripped Havana since July 9, when five Cubans entered the Czechoslovak Embassy, ostensibly seeking asylum.

He repeated his accusation that the United States has masterminded the asylum crisis, which has dragged on for 17 days, involving more than 45 Cubans entering or trying to enter embassies or diplomatic residences of Czechoslovakia, Spain, Italy, Switzerland and the United States. The United States and other foreign governments have denied any role in manipulating the Cuban asylum-seekers. Several diplomats have suggested that at least half of the Cubans who have entered foreign embassies are working with the Cuban state security apparatus and are not genuine asylum seekers.

In the course of his speech, Castro heaped scorn on the governments of the United States, Spain and Czechoslovakia and on Cubans who would try to leave the island by turning "embassies into travel agencies." He said Cubans were free to leave the island if they could receive visas from foreign countries, but not by taking refuge in embassies. He added sarcastically, "If the Yankees want to receive these very harrassed and persecuted people, let them bring their ships and visas."

Castro has blamed the United States for provoking the asylum crisis by not meeting its obligation under international agreements to accept Cubans who wish to emigrate. "These champions of human rights are cruel by not giving the opportunity to those who want to leave their country," he said.

Castro's remarks appeared not to amount to a policy shift, but rather to a warning to Cubans not to seek refuge in foreign embassies. In 1980, an asylum crisis spun out of control, leading to the flight of 125,000 Cubans from the port of Mariel. Diplomats say Castro is determined not to permit another such exodus, which in the current economic climate could provoke dangerous instability.

The Cuban leader ran through a list of grievances with the United States, saying President Bush is "obsessed" with harrassing Cuba. He mentioned TV Marti, the U.S. government television broadcast beamed at Cuba that has been jammed by Havana. So far, he said, Cuba has not retaliated. But he warned that Cuban radio transmitters are powerful enough to "make them dance the lambada if we wanted, even in the White House!"

Only the Soviet Union escaped Castro's rhetorical wrath. He said the Soviets, who give Cuba about $5 billion a year in aid, were doing everything they could to meet their previous obligations despite domestic difficulties.

"We have no complaints about the Soviets," he said. "The problems of the Soviet Union are greater than their willingness to . . . deliver the amounts agreed upon."

He said that Cuba's "situation with fuel supplies is tense, very tense," and he mentioned shortages of fertilizers, metals and lumber, all of which are important for Cuba's development. Some diplomats in Havana say that Castro lately has made a concerted attempt to portray the outside world as a galaxy of hostile powers intent on dominating and humiliating Cuba.

Castro's intention, the diplomats say, is to whip up a frenzy of Cuban nationalism and prepare people for long-term economic decline and the possibility of a draconian austerity program modeled on wartime contingency plans.

After running through a list of shortages afflicting the Cuban economy, Castro declared, "Our reaction is: Struggle! Struggle! Struggle! Resist! Resist! Resist!"

The crowd roared its approval.

Still, Castro left the door open to modifications in the Cuban system. He said the Fourth Communist Party Congress, scheduled for early next year, would consider "every measure possible to improve our socialism." He was not specific.

Before Castro's speech in this lovely, crumbling seaside city of 2 million inhabitants, all business ground to a halt as the prodigious Cuban state publicity machine issued last-minute appeals for people to go to the plaza.

The Committees for the Defense of the Revolution, the network of neighborhood organizations that serve as the central government's eyes and ears at the grassroots, were making door-to-door visits urging people to attend.

It was the first time since 1972 that Havana has hosted Castro's annual speech marking his failed attack on the Moncada barracks, the opening shot in his 5 1/2-year guerrilla war that toppled U.S.-backed dictator Fulgencio Batista.

The electoral defeat of Nicaragua's Sandinista government and the demise of socialism in Eastern Europe have left Castro increasingly isolated. In Miami, the fate of Havana's old ally has provoked a whirlwind of speculation among anti-Castro Cuban exiles that Castro will be the next to fall -- despite the absence of organized opposition.

All around Havana, Cubans say, lines grow longer, food and spare parts scarcer and the small conveniences of everyday life more difficult to find. Cuban magazines run lengthy articles on the shortage of food-packaging material. Meat and dairy products are in short supply. A hundred people wait in line for a half hour or more for a chance to buy some pineapples and plantains.

Cuba has even opened an unofficial channel of communications with Israel for the first time since Havana broke off relations with Tel Aviv in 1973, recently granting a leftist Israeli politician a visa, the Miami Herald reported last week.

Nevertheless, Cuba's ability to expand its international trade faces formidable obstacles, including the 25-year-old U.S. embargo and a severe shortage of hard currency and international credit.

"It's a slow squeeze," said a European diplomat here. "You won't see a sudden crisis, just a gradual, steady, irreversible slide."

Cuba's ties to the nations of what used to be the East Bloc were strong, and the upheaval in Europe has stunned Cubans and left officials scrambling for explanations. Castro has insisted that Cuba will safeguard socialist orthodoxy, but at the same time officials have encouraged a debate in preparation for the forthcoming party Congress, which is intended to "perfect" the Cuban system while not fundamentally altering it. END NOTES