HAVANA -- Fidel Castro said Tuesday that President Obama "misinterpreted" his brother Raul's sentiments toward the United States and bristled at any suggestion Cuba should free political prisoners or reduce official fees on money sent to the island from the U.S.

Raul Castro touched off a whirlwind of speculation that the U.S. and Cuba could be headed toward a thaw in nearly a half-century of chilly relations last week, when he said Cuban leaders would be willing to sit down with their U.S. counterparts and discuss "everything," including human rights, freedom of the press and expression, and political prisoners on the island.

Secretary of State Hillary Clinton said she welcomed the "overture," while Obama responded at the Summit of the Americas by saying Washington seeks a new beginning with Cuba. But he also said that Cuba should release some political prisoners and reduce official taxes on remittances from the U.S. as a sign of good will. 

That appeared to enrage Fidel Castro, 82, who wrote in an essay posted on a government Web site that Obama "without a doubt misinterpreted Raul's declarations."

The former president appeared to be throwing a dose of cold water on growing expectations for improved bilateral relations — suggesting Obama had no right to dare suggest that Cuba make even small concessions. He also seemed to suggest too much was being made of Raul's comments about discussing "everything" with U.S. authorities.

"Affirming that the president of Cuba is ready to discuss any topic with the president of the United States expresses that he's not afraid to broach any subject," Fidel Castro wrote of his 77-year-old brother, who succeeded him as president 14 months ago.

"It's a sign of bravery and confidence in the principles of the revolution," he said, referring to the rebel uprising that toppled dictator Fulgencio Batista and brought the Castros to power on New Year's Day 1959.

"Nobody should assume that he was talking about pardoning those sentenced in March 2003 and sending all of them to the United States, if the country were willing to liberate the five Cuban anti-terrorist heroes," Castro wrote.

He was referring to 75 leading political opposition leaders who were rounded up and imprisoned six years ago. Some 54 of them remain behind bars, though Raul Castro suggested last year that Cuba would be willing to liberate some political prisoners if U.S. authorities would free five imprisoned Cuban spies.

Castro compared the prisoners arrested in 2003 to exiles who attacked the island's southern coast during the disastrous Bay of Pigs invasion in 1961 and said they were "at the service of a foreign power that threatens and blockades our country," referring to charges they conspired with Washington to destabilize the communist system.

The ex-president had previously expressed his admiration for Obama, but this time Castro blasted the new U.S. president for showing signs of "superficiality."

He also defended Cuba's right to levy a 10 percent fee on every U.S. dollar sent to relatives on the island by Cuban-Americans, saying if the money arriving from abroad "is in dollars, all the more reason we should do it because it is the currency of the country that blockades us."

All top Cuban leaders routinely call the 47-year-old trade embargo against this country a blockade.

"Not all Cubans have family members overseas that send remittances," Castro said, adding that Cuba uses the revenue from fees on exchanging dollars to provide free health care, education and subsidized food to all of its population.