The Alba leaders held their seventh meeting in Venezuela
Cuban President Raul Castro has said he is willing to talk to Washington about everything, including human rights, political prisoners and press freedom.
His comments came hours after US President Barack Obama said Cuba needed to make the next move if there was to be further improvement in relations.
Mr Castro was speaking in Venezuela ahead of a Summit of the Americas.
Venezuelan President Hugo Chavez said he will veto any final declaration as Cuba is excluded from the meeting.
The summit, due to start in Trinidad, includes 34 Latin American and Caribbean countries.
The US has said the gathering is reserved for democratic nations.
Speaking to Latin American leaders in Venezuela, President Castro said he had sent word to the US government "in private and in public" that he is open to negotiations as long as it is "on equal terms".
There is still no formal contact between the Cuban authorities and the US government, but this is the latest in a series of exchanges which suggest that both sides appear to be making efforts to find a way to end the 50-year stalemate, our correspondent in Havana, Michael Voss reports.
Earlier this week, the US president announced that he was lifting restrictions on Cuban Americans visiting relatives on the island and sending money home.
Following the easing of US travel restrictions, Mr Obama said it was up to Havana to make the next move.
President Obama, who will attend the summit, said he wanted to "see whether Cuba is also ready to change" as the US tried to improve relations.
"We don't expect them to change overnight, that would be unrealistic. But we do expect that Cuba will send signals that they're interested in liberalising," said Mr Obama, during a visit to Mexico.
Mr Castro, who took over the presidency from his older brother Fidel last year, did not mention Mr Obama's comments specifically and stopped short of promising any concrete actions.
On Thursday, Venezuelan President Hugo Chavez said he will veto any final declaration at the Summit of the Americas because Cuba is excluded.
Mr Chavez spoke as he welcomed his closest Latin American allies at a meeting of the Alba group of nations in the Venezuelan city of Cumana.
He said a new organisation should be formed to replace the Organization of American States (OAS), whose members are meeting in Trinidad and Tobago.
"Why does Cuba continue to be mistreated?" Mr Chavez asked after welcoming Mr Castro. "We can't accept it."
"I hope the president of the United States is going to listen" at the OAS summit, he said.
A spokesperson for the US president said Mr Obama had no plans for a bilateral meeting with Mr Chavez during the Summit of the Americas.
Mr Castro recalled Cuba's victory against an invasion of US-backed exiles at the Bay of Pigs in April 1961, the Associated Press news agency reported.
"We are going to continue fighting," he said.
The Alba leaders, who include Mr Castro, Bolivian President Evo Morales and Nicaraguan President Daniel Ortega, are expected to announce the launch of a shared currency called the sucre.
Mr Chavez said it would begin to circulate by January 2010.