MEXICO CITY -- The new presidents of the United States and Cuba, in a surprisingly direct exchange, appeared to open the door Thursday for negotiations toward a new relationship between the two countries divided by 90 miles of water and 50 years of cold war.
After removing some of the restrictions that lock Americans and their money out of Cuba in what he called a show of good faith, Barack Obama said Thursday that it was up to Havana to take the next step.
Within hours, Raul Castro replied from a summit in Venezuela: "We have sent word to the U.S. government in private and in public that we are willing to discuss everything -- human rights, freedom of the press, political prisoners, everything."
That was the boldest and most conciliatory language Castro or his brother Fidel -- who handed him the presidency a year ago after falling ill -- have used with any U.S. administration since that of Dwight D. Eisenhower in early 1961, when the nations broke off relations. It appeared to be a transcendent development, the best opportunity for talks in a half-century.
Raul Castro has previously said he would be willing to discuss all issues with Obama. But Cuban officials have historically bristled at the suggestion that they might discuss human rights or political prisoners with the Americans, saying such matters are none of the Yankees' business.
Talking about the issues, of course, is no guarantee that Cuba is ready to offer the reciprocity Obama says the U.S. needs to see before making any more changes in its policies toward the island. And Fidel Castro, who still pens enormously influential columns from the sidelines of power, could still throw a bucket of cold water on the conciliation.
Indeed, Obama said a relationship frozen for 50 years "won't thaw overnight."
But their words seemed as historic as any that leaders of the two nations have made to one another.
Relations warmed briefly during Jimmy Carter's administration, which featured short-lived direct flights between Miami and Havana and the opening of interests sections that provide some contact in lieu of embassies. But that short honeymoon ended with a refugee crisis that saw about 125,000 Cubans flee to the United States from the Mariel port west of Havana.
Warming relations under Bill Clinton also were put in the freezer after Cuban fighter jets shot down two civilian planes off the island's coast, killing the four exiles aboard.
Raul Castro said his only conditions for talks now are that Washington treat them as a conversation between equals and respect "the Cuban people's right to self-determination."
Earlier this week, Obama lifted restrictions on visits and money sent to Cuba by Americans with families there -- steps he called "extraordinarily significant" for those families.
On a visit to Mexico City, Obama said Cuba needs to reciprocate to his overtures with actions "grounded in respect for human rights," possibly including lifting its own restrictions on Cubans' ability to travel and to voice their opinions.
President Castro did not mention Obama's comments specifically -- and stopped short of promising any action.
"We're willing to sit down to talk as it should be done, whenever," he said, while also condemning decades of efforts by Washington to undermine the Cuban government. "What's going on is that now ... whoever says anything, they immediately start (talking about) democracy, freedom, prisoners."
Both leaders signaled that deep problems remain in their relationship.
Obama said the U.S. won't unilaterally end its trade embargo against Cuba, even though the policy is widely seen as a failure that has complicated U.S. relations throughout Latin America and the Caribbean.
Castro called for the release of five Cubans imprisoned in the U.S. after being convicted of espionage, and denounced U.S. funding for opponents of his government.
"I'm confirming it here today: If they want the freedom of those political prisoners, who include some confessed terrorists ... free our prisoners and we'll send them to you with their families and whatever they want," he said.
Obama spoke at a news conference after meeting with Mexican President Felipe Calderon, who called the U.S. embargo a failed strategy. Asked what the U.S. should do on Cuba to improve its image across Latin America, Calderon said "we do not believe that the embargo or the isolation of Cuba is a good measure for things to change."
"We stand ready to discuss with Cuba additional steps that could be taken," she said. "But we do expect Cuba to reciprocate."
"We would like to see Cuba open up its society, release political prisoners, open up to outside opinions and media, have the kind of society that we all know that would improve the opportunities for the Cuban people and for their nation," she said.
Castro spoke at a meeting of leftist leaders in the seaside Venezuelan city of Cumana, in advance of the Summit of the Americas in Trinidad, where Obama and most leaders of the Americas will meet beginning Friday.
Castro is not invited because his country is not democratic -- Venezuelan President Hugo Chavez called the U.S. position a "show of disrespect."