WASHINGTON -- A swelling stream of Cuban refugees was expected to flood toward the United States on Thursday after Washington rejected Havana's offer of talks to end the biggest exodus from the communist-ruled island since the 1980 Mariel boatlift.


Cuba's foreign minister and U.N. ambassador both said Wednesday that the government of President Fidel Castro was ready to discuss the mass migration with the United States.


Speaking at a news conference during a visit to Santiago, Chile, Foreign Minister Roberto Robaina said the talks should take place without preconditions from either side, adding that Cuba would not accept a dialogue "in which one side presides and the other listens."


But the Clinton administration, which has vowed to turn its Guantanamo Naval Base at the southern tip of Cuba into a vast detention camp rather than allow the refugees into the United States, rejected the idea of negotiations out of hand.


"I think the problem of engaging with Castro at that level is that there is nothing we can see that can be gained," Undersecretary of State Peter Tarnoff said on ABC television's "Nightline" program.


"It should be clear to Castro ... what he has to do is take seriously the plight of his own people and reform. The solution to this crisis lies in Cuba," he said.


Tarnoff spoke at nearly the same time that Castro, in a speech on Cuban state television, called the decision to hold the refugees at Guantanamo "an absurd response" to the crisis.


Castro acknowledged that his government had begun turning a blind eye to people leaving the island on flimsy rafts and makeshift boats. But he said the flood of boat people into the Straits of Florida was a problem born of years of erroneous U.S. policy.


Any solution would have to involve "analyzing causes and looking for serious solutions," Castro said, adding the United States would have to change course on issues -- including its immigration policy and the longstanding economic embargo against Cuba.


He scoffed at President Clinton's effort to stem the flow of boat people by diverting them to Guantanamo, saying Washington was only creating a "concentration camp" for Cubans.


The flood of refugees has continued unabated since Clinton vowed Saturday to keep them out of the United States. By mid-afternoon Wednesday, the U.S. Coast Guard had picked up 1,159 Cubans, bringing the total rescued in just two days to more than 4,400.


Defense Secretary William Perry said the U.S. plan to deal with the exodus would be to vastly expand the refugee camp at Guantanamo and hold Cubans there indefinitely -- if need be -- until Cuba repatriates them.


Perry said 9,000 Cubans has been picked up to date and 2,000 were at Guantanamo naval base at the time he spoke.


As of Wednesday there were facilities at Guantanamo for more than 23,000 refugees. "By the end of the week, we will have facilities for 30,000 and by the end of next week, facilities for 40,000," Perry said.