President Obama says he seeks an "equal partnership" between the US and Latin America
President Barack Obama has said the US seeks a "new beginning" with Cuba and an "equal partnership" with all the nations of the Americas.
Mr Obama was addressing Latin American and Caribbean leaders at the Summit of the Americas in Trinidad and Tobago.
The summit follows a thaw in US-Cuban relations. Cuba is not at the summit.
Earlier, US Secretary of State Hillary Clinton welcomed an offer for talks from Cuban President Raul Castro, saying the old US policy had failed.
Mr Castro said on Thursday that he was ready to talk about "everything" with the US, including human rights, political prisoners and freedom of the press.
His comments came after the US eased restrictions, allowing Cuban-Americans to visit relatives in Cuba and send money home more easily.
Call for change
Speaking to leaders gathered in Port of Spain, Mr Obama declared: "The US seeks a new beginning with Cuba."
"I know there is a longer journey that must be travelled to overcome decades of mistrust, but there are critical steps we can take toward a new day," he said.
Cuba is excluded from the summit, which includes 34 members of the Organisation of American States (OAS), though Latin American leaders have been calling for Cuba to be readmitted.
The US has not maintained high-level diplomatic relations with Cuba since 1960, a year after Fidel Castro led the island's revolution.
Washington also imposed partial trade sanctions in 1960, expanding it to a full economic embargo in 1962.
Under former US President George W Bush, measures were put in place to support Cuban opposition and "hasten the end" of the Castro regime.
However, speaking on Friday in the Dominican Republic, Mrs Clinton acknowledged that US policy towards Cuba had "failed" and said Washington was "taking a very serious look at how to respond."
Addressing the summit, Mr Obama said he wanted to move forward with a sense of "equal partnership" with all the nations of the Americas despite decades of mistrust.
First Bush, now Obama - Chavez meets a new US president
"I am here to launch a new chapter of engagement that will be sustained throughout my administration," he said to applause from the delegates.
Mr Obama earlier greeted and shook hands with Venezuela's President, Hugo Chavez, during an impromptu meeting.
Photographs released by the Venezuelan government showed Mr Chavez - one of the Bush's administrations most strident critics - smiling and clasping hands with Mr Obama at the start of the summit.
Before the summit began Mr Chavez appeared to chastise the US for its approach to Cuba, which is not a member of the OAS.
In a pre-summit statement, he also said that "there is more democracy in Cuba than in the United States".
But he greeted the US president warmly when the opportunity arrived, gripping the Mr Obama's hand in welcome.
"I greeted Bush with this hand eight years ago; I want to be your friend," Mr Chavez told Mr Obama, according to a Venezuelan presidential press office statement.
"It was very, very short," said a US official. "The president shook his hand, smiled and then went back to his position in the line."
Summit leaders are also expected to address the economic downturn and the region's energy and security needs at the weekend talks.