A top Cuban official has warned dissidents they will face consequences if they accept funds from a new US plan to promote political change in Cuba.
Fidel Castro: Cuba's dominant presence for nearly 50 years
Cuba's National Assembly president, Ricardo Alarcon, said the plan was a "politically delirious provocation".
President George W Bush on Monday approved the $80m (£43m) fund which he said would help boost democracy in Cuba.
A US commission has been analysing policy on Cuba after the eventual death
of Fidel Castro who is 80 next month.
Mr Alarcon told the Spanish news agency, Efe, that any dissidents who "conspired " with Washington and accepted its funding would have to "face the consequences".
It would be a crime to accept such money under Cuban law, as it would be in any country, Mr Alarcon aid.
Mr Alarcon has said the US aims at "regime change"
"Imagine that someone in the US were to be supported, trained, equipped and advised by a foreign government, that in itself would be a crime. It would be a serious crime in the US, punished with far more years in prison than here in Cuba," Mr Alarcon said.
The plan drew a mixed reaction among dissidents in Havana.
Several expressed concern that the new funding could serve as a pretext for the Cuban authorities to step up the pressure on them.
"I really appreciate the solidarity of the United States government and people, but I think that this report is counterproductive," dissident journalist Oscar Espinosa Chepe told foreign news agencies on Monday.
But Vladimiro Roca, a former political prisoner, said he would accept any aid, the Miami Herald newspaper reported.
"'It would be more than welcome,"' he said in a telephone conversation, adding that the Cuban government's aim was to dissuade dissidents from accepting the money.
"We need materials, equipment, clothes, everything."
The plan also provoked a strong reaction in Cuba's close regional ally, Venezuela.
"They've launched what I consider a new imperialist threat," Venezuelan President Hugo Chavez said in a nationally televised speech.
"They've publicised a plan of transition, they think Fidel is going to die."
President Castro, in power since 1959, is preparing to celebrate his birthday in August.
The Cuban government has made recent moves to give a higher profile to his designated successor, his 75-year-old brother Raul Castro.
The report, drawn up by the US Commission for Assistance to a Free Cuba, includes measures such as enforcing sanctions already in place against the communist regime and "providing uncensored information" for Cubans who want change.
Since the fall of the US-backed dictatorship of Fulgencio Batista in 1959, Cuba has been a one-party state led by Mr Castro.
Since 1961, the US has maintained a strict economic embargo against Cuba.