The US and Cuba have announced that the two countries would reopen their embassies this month, signalling a return to normalcy since the Cold War.
In his address from the White House Rose Garden on Wednesday, US President Barack Obama called the move a "historic step forward" and said: "You can't hold the future of Cuba hostage to what happened in the past."
He said it was time for the US to re-establish diplomatic relations with Cuba. Reports say the two former rivals agreed to unfreeze ties on 20 July, possibly reopening embassies in Washington and Havana.
Obama also said that working more closely with Cuba would allow the US to address human rights issues. "We will not hesitate to speak out when we see actions that contradict those values," Obama said.
A note from Obama was delivered at a brief ceremony at the Cuban Foreign Ministry in Havana, ending the 54-year-long stalemate that began during the Eisenhower administration.
In his letter to Obama, President Raul Castro said, "We want to develop a friendship between our two nations that is based on the equality of rights and the people's free will."
He noted that each nation must respect the territorial integrity of the other and they should not interfere in each other's political affairs.
In Cuba, a government statement said President Castro would send Foreign Minister Bruno Rodriguez to open the Cuban embassy in Washington on 20 July. The delegation will include "prominent representatives of Cuban society", AP reported.
Earlier in May, the US removed Cuba from its list of state sponsors of terror, but trade and travel embargo remain a hurdle to be overcome with Cuba alleging violation of international laws.
"There could be no normal relations between Cuba and the United States as long as the economic, commercial and financial blockade continues to be fully implemented, causing damage and scarcities to the Cuban people," reads a Cuban foreign ministry statement received by CNN.
While many trade and travel prohibitions have been relaxed, many remain that can only be removed by legislation.
Obama has asked Congress to lift an embargo that prevents Cubans from travelling or doing business in the US. But Congress, controlled by Republicans, is not inclined to do so.
Lastly, Obama announced that "later this summer, Secretary John Kerry will travel to Havana formally to proudly raise the American flag over our embassy once more".