The US and Cuba will on Wednesday announce the opening of embassies in each other's capitals, a major step in re-establishing diplomatic ties severed in 1961, a senior US official has said.
Relations had been frozen since the early 1960s when the US broke links and imposed a trade embargo.
This was in response to the revolution in 1961 which brought Fidel Castro's Communist government to power.
But the US and Cuba agreed to normalise relations at the end of 2014.
Since 1977, the US and Cuba have operated diplomatic missions called "interests sections" in each other's capitals under the legal protection of Switzerland. However, they do not enjoy the same status as full embassies.
US officials said President Barack Obama would make a formal announcement from the White House at 15:00 GMT on Wednesday.
It is still not clear exactly what the date will be for opening the embassies, but it is likely to be in mid-July, says the BBC's Cuba correspondent Will Grant.
The US State Department must give Congress two weeks' warning before the embassy can open, he adds.
It is the latest major milestone in a thawing process between the two countries' relations, which started with secret negotiations and was announced last December.
In April, President Obama and his Cuban counterpart, Raul Castro, met for the first formal talks between the two countries' leaders in more than half a century.
A month later, the US removed Cuba from its list of state sponsors of terrorism. Plans to resume ferry and air services between the US and Cuba were also announced.
Despite the new transport links, a Cuba travel ban is still in place for US citizens.
Cuba is also still subject to a US arms embargo which has been in place since 1962, though President Obama has urged Congress to lift it.
The US broke off diplomatic relations with Cuba in 1959 after Fidel Castro and his brother Raul led a revolution toppling US-backed President Fulgencio Batista. The Castros established a revolutionary socialist state with close ties to the Soviet Union.
In December 2014, the two presidents made a surprise announcement saying they would seek to re-establish diplomatic ties, ending more than 50 years of ill-will.