KINGSTON, JAMAICA -- A sharp reduction in U.S. economic aid to the island nations of the Caribbean has angered the region, many of whose democracies have been among the most dependable allies of the United States.

The cut in aid, made last fall when the United States was searching for funds with which to assist emerging democracies of Eastern Europe, has prompted occasionally bitter remarks that Washington is shunting aside old friends in its rush to embrace new ones. And there are warnings that the region's economic problems, if not tended to now, inevitably will wash up on America's shores.

In private conversations, several officials said they viewed Cuban President Fidel Castro's continuing rule as a kind of insurance policy, guaranteeing a minimum level of U.S. support in the Caribbean.

Castro's downfall, they said, could mean a complete collapse of America's concern with the region. Caribbean nations also fear that they could lose trade benefits when the European Community carries out its economic integration in 1992. That, combined with the decline in U.S. aid, has stirred new moves toward integration and cooperation in the Caribbean.

"The situation is compelling everyone to look at regional integration," said David H. Coore, Jamaica's foreign minister. "If developing countries in this region don't start working together, the prospects of not being further marginalized are fairly remote."

While the Caribbean is not alone among areas of the world expressing anxiety at losing U.S. aid to Eastern Europe, its proximity and close economic and cultural ties to the United States make it unusual.

The region is one of the few with which the United States runs a trade surplus. A recent demand for nurses in Florida translated immediately into a severe nurse shortage in Jamaica as Jamaican nurses left the island by the hundreds to take jobs in the United States. And on any number of Caribbean islands, it seems as if every popular American tune -- including the theme from television's "Sesame Street" -- has been set to a reggae beat.

U.S. officials have been busy reassuring their counterparts in the region that there is no long-term move afoot to reduce American support. Nonetheless, Washington made cuts last fall.

Economic aid to the region, originally planned at $60 million for the 1990 fiscal year, was at first cut to zero before about a third of it was restored. U.S. diplomats in Jamaica, which had been slated to receive the largest chunk of the aid -- $25 million -- fired off a memo expressing their concern.

Since then, a portion of Jamaica's funding, $13.7 million, has been restored, in part because of a trip by Vice President Quayle to the island in January and a visit by Prime Minister Michael Manley to Washington last month in which he lobbied for more aid. But the Dominican Republic and some of the smaller islands of the eastern Caribbean were left with little economic assistance.

There are other types of U.S. assistance to the Caribbean that have not been affected by the reductions, including food aid and development programs, which together will total more than $160 million this fiscal year. However, many Caribbean nations, especially Jamaica, depend heavily on economic aid -- a direct infusion of foreign exchange -- to help meet steep payments on foreign debt.

Although U.S. economic aid to the region has fluctuated, this year's total of a little more than $20 million represents a sharp decline from recent years. In part, the decline reflects shifting priorities in Washington and tighter foreign aid budgets, burdened by new packages for Eastern Europe, Panama and Nicaragua and constricted by large commitments to Israel, Egypt, Turkey, Pakistan and the Philippines.

But the reduction also is an indication of the changing political dynamics of the Caribbean. In 1987, when the region received $82 million in U.S. economic aid, Cuba seemed to loom as a greater threat to regional stability. Haiti had shed the 29-year Duvalier family dictatorship the year before, and memories of the political turmoil in Grenada and the resulting invasion had not yet faded.

Today, Cuba is preoccupied with its troubled domestic economy. Haiti has staggered through three years in which the promise of democracy has been thwarted. Despite social problems and heavy debt burdens that make it difficult to improve real living standards, the region's democracies seem secure, and economies are growing, if unevenly.

Nonetheless, many in the region caution that the seeming tranquility should not be misread. "History has shown that the Caribbean has always been a place that attracts predators," said Darnel R. Campbell, attorney general of St. Vincent. "So any reduced assistance could lead to the Caribbean turning to other funds, and that means U.S. influence would wane."

At a regional conference on laundering of drug money held this month in Aruba, a number of officials chafed at suggestions by the United States that they toughen enforcement to block tainted money from entering their countries. "They have to start putting their money where their mouth is," said Harold Henriquez, a diplomat from the Netherlands Antilles.

"No one disagrees with their arguments, but there are not enough resources to go around," said a State Department official. "The Caribbean seems friendly, stable and close by. While there may be clouds on the horizon, it's not involved in the political problems of Central America and doesn't have the tremendous political reforms of Eastern Europe."

But to many Caribbean officials, the U.S. view is shortsighted. While there may be no coups or riots or revolutions under way, leaders in the region say the economic underpinnings of their societies are stretched to the limit by debt and dwindling prices for commodities.

"The underlying economic situation is so bad that not only is there no guarantee that stability will continue, but the probability is that it won't," said Coore, the Jamaican foreign minister.

In Jamaica, there is a sense of irony at the U.S. policy shifts. Washington was worried in the 1970s, when Manley, serving his first stint as prime minister, launched a socialist program and made diplomatic common cause with Castro.

Defeated in 1980, he returned to win the nation's top job last year as an ideological convert to free-market economics. He has yet to renew relations with Castro, which were broken under the premiership of Edward Seaga in the 1980s.

But now that Manley has come around to Washington officials' way of looking at the world, said one Jamaican official, "they hardly have the time of day for him."

U.S. officials, faced with such arguments, say that economic aid is no cure-all for the islands' economies, even those as depressed as Jamaica's, which bears $4.6 billion in debt.

They contend that the region needs new investment and investment guarantees more than it needs new aid, and they cite the Caribbean Basin Initiative, a program of trade benefits and investment incentives initiated by the Reagan administration, as the correct focus for U.S. policy in the region.

That approach strikes a chord here, especially with the business community, which is loath to project an image of dependence and distrusts the politics of American aid as an endlessly fickle roll of the dice.

"U.S. politics is like Hollywood," said Delroy Lindsay, director of the Private Sector Organization of Jamaica. "It's Michael Jackson today, John Wayne tomorrow, and the next day, Bruce Springsteen."

Business leaders are supporting the proposals of a number of leaders in the region, including Manley, who have called for regional unity in response to international challenges. There are proposals now in the works to create a regional stock market and a free-trade zone.

The proposals are driven in part by fears that the region will lose its trade preferences for sugar, bananas and other commodities once the major nations of Western Europe unify their economies after 1992. European beet sugar could be substituted for Caribbean cane sugar, for instance.

In the islands that are former British colonies, in particular, the impulse to unify in the face of a challenge from the former colonial masters is deeply ingrained. Jamaicans are quick to use a sports metaphor, pointing out that Britain dominated international cricket until the islands of the West Indies banded together to form a single team. Since then, they say, the West Indies has been the team to beat.