COZUMEL, Mexico (AP) _ Three Latin American presidents held an unscheduled meeting with Cuban President Fidel Castro on Wednesday but offered his beleaguered Caribbean nation little besides expressions of solidarity.

Castro's meeting with the leaders of oil-rich Mexico, Venezuela and Colombia touched off speculation he would lobby for the fuel his Caribbean island nation needs so desperately.

But Castro said he didn't ask for oil because Cuba doesn't have the cash to pay for it. He said Cuba is suffering from the loss of Soviet subsidies that kept it in oil for 30 years and from low prices for its main export - sugar.

''We have to find other sources of petroleum and it isn't easy,'' he said. ''All of our sugar at current world trash-prices wouldn't pay for the oil we need.''

President Carlos Andres Perez of Venezuela said the door was closed to the San Jose Pact, which provides Caribbean and Central American countries with oil from Mexico and Venezuela at favorable prices.

''There is no room for the option that other countries can enter,'' he said.

Cuba's economy has sunk to an all-time low. Everything from cigars and shoes to food and fuel is rationed.

A communique from presidents Andres Perez, Carlos Salinas de Gortari of Mexico and Cesar Gaviria of Colombia called for Cuba's integration into the Latin American community as vital to the ''development and stability of the Caribbean region.''

It echoed calls from Latin leaders - and Castro - for a Latin America united to face a changing, post-Cold War world.

Latin leaders scold Castro for clinging to an orthodox, one-party socialist line in a region that has undergone a democratic revolution. But Salinas said no conditions were put upon Cuban re-entry.

Andres Perez asked the United States to lift its three-decade economic blockade of Cuba.

Castro said Latin America is Cuba's natural venue and Latin unity is the only defense against United States domination.

Salinas said Castro was invited because ''what happens in Cuba is going to have repercussions in our region.''

''We will follow with great interest the internal changes that Cubans make of their own free will,'' he said.

Salinas praised Cuba's attempts to attract foreign investment and increase commercial ties in the region.

Castro has turned to Latin America in his search for new trading partners for his import-dependent island. His overtures have been generally welcomed.

Mexico, Venezuela and Colombia are especially important to Cuba because of oil - is such short supply in Cuba that commuters ride bicycles and farmers use oxen.

But Andres Perez told reporters Cuba was not going to be a charity case.

''We're not in any condition to help anyone,'' he said. ''We're rescuing the economies of our own countries.''

Cuba is courting investment in tourism and other areas and says it will offer Latin investors special terms.

Mexico has a dynamic tourism industry; it also imports sugar and nickel, which Cuba produces. Colombia has suggested Cuba might refine some of its crude in exchange for fuel.

Colombia recently established diplomatic ties with Cuba and stands to gain from warmer relations. Cuba is thought to have influence over the Marxist guerrillas who have been battling Colombia's government for 30 years.