Cuba said today it would not allow a U.N. human rights envoy to visit the island following the most severe crackdown in decades on opponents of President Fidel Castro.

Facing growing international isolation, Cuba also said it was considering withdrawing its request to join a European Union preferential trade and aid accord because of European criticism of its rights record.

Europe and the United Nations were not the only targets of official Cuban anger. Foreign Minister Felipe Perez Roque said Cuba reserved the right to shut down the U.S. diplomatic mission. Cuban officials have accused U.S. diplomats of organizing efforts by dissidents to undermine the Caribbean island's one-party Communist state.

In the past month, in a move to stamp out opposition to Castro, Cuba has rounded up 75 dissidents and sentenced them to prison terms of up to 28 years.

The Cuban government also reacted angrily to a report that the Bush administration was considering suspending family remittances by Cuban Americans, but said its socialist economy would survive the blow.

Cash sent to Cuba by relatives in the United States is a vital source of income for families here, and is estimated to total about $1 billion a year.

The New York Times reported Thursday that the Bush administration was studying steps to punish the Cuban government for the recent crackdown.

"More than four decades of revolution have demonstrated that our country is capable of facing any threat and defeating sinister plans of all kinds," a Cuban government statement said.

"The punished will be many families . . . and, what is worse, many elderly people who depend on these remittances," said the statement, published on the front page of the Communist Party daily newspaper Granma.

The Cuban statement, which local analysts said they thought was probably written by Castro, said the dollar remittances went a long way in Cuba because the socialist state subsidizes food and rent.

"The Cuban economy and its social services can survive the suspension of the alleged grand benefits of those remittances," it said.

In Washington, U.S. officials said they might consider new steps to pressure Cuba, but so far discussions remained at a low level of government.

"People at the working level [are] looking at the more harsh tactics of the regime and thinking about what can we do," a U.S. official said. "I'm not aware of anything that's put down on paper," he said.

White House spokeswoman Claire Buchan said on Thursday, "We'll continue to work with independent Cuban civil society and with the Cuban people, and are willing to consider steps to advance that policy goal in this climate."

The Bush administration has already moved to curb travel to Cuba by Americans involved in educational programs, and has vowed to veto a move in Congress to lift a ban on American tourist travel to Cuba.